Using importance resampling to reduce the memory incoherence of light sampling

ABSTRACT

Devices, systems, and techniques to incorporate lighting effects into computer-generated graphics. In at least one embodiment, a virtual scene comprising a plurality of lights is rendered by randomly sampling a set of lights from among the plurality of lights prior to rendering a frame of graphics. A subset of the set of lights is selected and used to render pixels within one or more portions of the frame.

CLAIM OF PRIORITY

This application claims the benefit of U.S. Provisional Application No.63/068,906 titled “RESAMPLING TECHNIQUE FOR RESERVOIR-BASED LIGHTING,”filed Aug. 21, 2020, the entire contents of which is incorporated hereinby reference.

FIELD

At least one embodiment pertains to computer graphics. For example, atleast one embodiment pertains to processors or computing systems used torender graphical images using various novel techniques described herein.

BACKGROUND

The handling of lights in computer graphics can consume significantamounts of time, memory, processing power, and other computingresources. This is particularly true for techniques, which may includebut are not limited ray tracing, that are intended to produce goodvisual quality, and for cases where many lights are included in a scenethat is to be rendered. Techniques for handling lights in computergraphics may therefore be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system employing light resampling torender a virtual scene, in accordance with at least one embodiment;

FIG. 2 illustrates an example of a process of rendering a frame of avirtual scene by at least sampling from a list of scene lights andresampling from memory portions, in accordance with at least oneembodiment;

FIG. 3 illustrates an example of a process for rendering a frame of avirtual scene by resampling from a memory portion, in accordance with atleast one embodiment;

FIG. 4 illustrates an example of lights in a virtual are, in accordancewith at least one embodiment;

FIG. 5 depicts an example of random selection of lights from a list ofscene lights, in accordance with at least one embodiment;

FIG. 6 depicts an example of rendering tiles based on a selection of oneor more pre-sampled subsets of lights, in accordance with at least oneembodiment;

FIG. 7 is an illustration of reservoir-based spatiotemporal importanceresampling (“ReSTIR”) candidate selection using a gather approach, inaccordance with at least one embodiment;

FIG. 8 is an illustration of ReSTIR candidate selection using a scatterapproach, in accordance with at least one embodiment;

FIG. 9 is an illustration of subpool reshuffling, in accordance with atleast one embodiment;

FIG. 10 is an illustration of rendering a frame using multiple opentiles, in accordance with at least one embodiment;

FIG. 11 is an illustration of an example process comprisingpre-randomization and render-time stages, in accordance with at leastone embodiment;

FIG. 12 illustrates an exemplary data center, in accordance with atleast one embodiment;

FIG. 13 illustrates a processing system, in accordance with at least oneembodiment;

FIG. 14 illustrates a computer system, in accordance with at least oneembodiment;

FIG. 15 illustrates a system, in accordance with at least oneembodiment;

FIG. 16 illustrates an exemplary integrated circuit, in accordance withat least one embodiment;

FIG. 17 illustrates a computing system, according to at least oneembodiment;

FIG. 18 illustrates an APU, in accordance with at least one embodiment;

FIG. 19 illustrates a CPU, in accordance with at least one embodiment;

FIG. 20 illustrates an exemplary accelerator integration slice, inaccordance with at least one embodiment;

FIGS. 21A and 21B illustrate exemplary graphics processors, inaccordance with at least one embodiment;

FIG. 22A illustrates a graphics core, in accordance with at least oneembodiment;

FIG. 22B illustrates a GPGPU, in accordance with at least oneembodiment;

FIG. 23A illustrates a parallel processor, in accordance with at leastone embodiment;

FIG. 23B illustrates a processing cluster, in accordance with at leastone embodiment;

FIG. 23C illustrates a graphics multiprocessor, in accordance with atleast one embodiment;

FIG. 24 illustrates a graphics processor, in accordance with at leastone embodiment;

FIG. 25 illustrates a processor, in accordance with at least oneembodiment;

FIG. 26 illustrates a processor, in accordance with at least oneembodiment;

FIG. 27 illustrates a graphics processor core, in accordance with atleast one embodiment;

FIG. 28 illustrates a PPU, in accordance with at least one embodiment;

FIG. 29 illustrates a GPC, in accordance with at least one embodiment;

FIG. 30 illustrates a streaming multiprocessor, in accordance with atleast one embodiment;

FIG. 31 illustrates a software stack of a programming platform, inaccordance with at least one embodiment;

FIG. 32 illustrates a CUDA implementation of a software stack of FIG. 31, in accordance with at least one embodiment;

FIG. 33 illustrates a ROCm implementation of a software stack of FIG. 31, in accordance with at least one embodiment;

FIG. 34 illustrates an OpenCL implementation of a software stack of FIG.31 , in accordance with at least one embodiment;

FIG. 35 illustrates software that is supported by a programmingplatform, in accordance with at least one embodiment;

FIG. 36 illustrates compiling code to execute on programming platformsof FIGS. 31-34 , in accordance with at least one embodiment;

FIG. 37 illustrates in greater detail compiling code to execute onprogramming platforms of FIGS. 31-34 , in accordance with at least oneembodiment;

FIG. 38 illustrates translating source code prior to compiling sourcecode, in accordance with at least one embodiment;

FIG. 39A illustrates a system configured to compile and execute CUDAsource code using different types of processing units, in accordancewith at least one embodiment;

FIG. 39B illustrates a system configured to compile and execute CUDAsource code of FIG. 39A using a CPU and a CUDA-enabled GPU, inaccordance with at least one embodiment;

FIG. 39C illustrates a system configured to compile and execute CUDAsource code of FIG. 39A using a CPU and a non-CUDA-enabled GPU, inaccordance with at least one embodiment;

FIG. 40 illustrates an exemplary kernel translated by CUDA-to-HIPtranslation tool of FIG. 39C, in accordance with at least oneembodiment;

FIG. 41 illustrates non-CUDA-enabled GPU of FIG. 39C in greater detail,in accordance with at least one embodiment;

FIG. 42 illustrates how threads of an exemplary CUDA grid are mapped todifferent compute units of FIG. 41 , in accordance with at least oneembodiment; and

FIG. 43 illustrates how to migrate existing CUDA code to Data ParallelC++ code, in accordance with at least one embodiment.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth toprovide a more thorough understanding of at least one embodiment.However, it will be apparent to one skilled in the art that theinventive concepts may be practiced without one or more of thesespecific details.

In at least one embodiment, an embodiment of a method for renderingcomputing graphics, incorporating reservoir-based lighting techniquessuch as reservoir-based spatiotemporal importance resampling (ReSTIR),comprises adaptations which optimize usage of computer hardware andmemory, including issues such as memory access latency, cache coherence,cache utilization, thrashing, and so forth.

Embodiments disclosed herein may be used in a variety of applications,devices, and circumstances, including those described herein. Techniquesdescribed herein may be utilized to render complex graphical scenes,such as those that may be generated in videogames, special effects,computer animation, computer-aided design, and so forth.

In various embodiments, techniques described herein are used to rendergraphical scenes in cases where high rendering speed is desired. Forexample, some of the operations and techniques described herein arecapable of being performed prior to rendering a frame of computergraphics, or with periodicity that is less than per-frame, to improvethe per-frame efficiency of rendering.

In various embodiments, techniques described herein are useful tonon-graphical applications and problem spaces that share characteristicssimilar to rendering or ray-tracing. For example, embodiments describedherein may be adapted for use in simulating effects of acoustic orelectromagnetic transmissions involving many emitters.

FIG. 1 illustrates an example of a system employing light resampling torender a virtual scene, in accordance with at least one embodiment. Inthe example 100 of FIG. 1 , a computing device 102 generates graphicaloutput to drive a display on screen 108.

In at least one embodiment, computing device 102 generates graphicaloutput using a graphics pipeline 104 and a graphics card 106. In atleast one embodiment, a graphics card 106 comprises one or moreprocessors, such as graphics processing units. In at least oneembodiment, graphics pipeline 104 comprises software, hardware, orcombinations of software and hardware to generate graphical output. Agraphics pipeline 104 may generate graphical output according to amulti-stage process, such as a process comprising the stages 110-118depicted within graphics pipeline 104 in FIG. 1 . Although the stages110-118 are depicted in FIG. 1 as a sequence, embodiments may omit someof the depicted stages 110-118, perform some of the operations 110-118in an order other than what is depicted, such as in parallel, or includestages in addition to those depicted in FIG. 1 . Accordingly, the orderdepicted in FIG. 1 should not be construed in a manner which would limitpotential embodiments to only those that conform to the depicted order.

In at least one embodiment, a graphics pipeline 104 comprises software,hardware, or a combination of hardware and software to implement amultiple-stage process for converting application data to graphical datasuitable (with or without certain post-pipeline steps) for display byscreen 108. For example, graphics pipeline 104 may generate a frame ofvideo data that can then be converted to a signal to drive the displayof the frame on screen 108. In at least one embodiment, these stages mayinclude an application stage 110, geometry stage 112, transformationstage 114, lighting and shading stage 116, and rasterization andtexturization stage 118.

In at least one embodiment, one or more of the stages 110-118 utilize alight sampling algorithm, including but not necessarily limited toReSTIR, to incorporate lighting effects into the rendering of a virtualscene.

In at least one embodiment, a virtual scene 120 comprises a simulated orcomputer-generated environment, such as a landscape, building, playingfield, or other area. A virtual scene 120 may sometimes be referred to,or comprise, a virtual environment. A virtual environment may beassociated with data structures, graphical assets, and other data thatdefine the contents and structure of the virtual environment. Forexample, in at least one embodiment, a virtual scene is based on avirtual environment which comprises a wireframe model of a landscape,various textures and objects residing within the scene, and so forth.The virtual environment may further comprise lights placed at variouspositions within the scene.

In some cases, a large number of such lights may be present, which canpresent a number of challenges when rendering depictions of the virtualscene 120. Handling many lights is a difficult problem in computergraphics, particularly for algorithms that are based on ray tracing. Forexample, one approach to rendering a virtual scene would be to evaluateall light sources in the scene for each shaded point. However,increasing the light count may also increases the number and complexityof rays that are to be traced, and thereby may also increase the time,computing resources, and complexity of the rendering process.

In at least one embodiment, a subset of lights is selected from a list122 of all of the lights in the virtual scene 120. The subset isselected based on an at least partially random process, and the selectedsubset is stored in a portion of memory 124. In at least one embodiment,the selected subset is stored in a record of a data structure thatcorresponds to a subdivision, or cell, of a virtual scene. In otherembodiments, the selected subset is not tied to or associated with anyparticular region of the virtual scene. In other embodiments, lights arestochastically selected according to a probability that is proportionalto the lights intensity or overall importance to the scene. In otherembodiments, lights are stochastically selected according to aprobability that is proportional to the importance of a given light'scontribution to a subdivision of the virtual scene. Stochastictechniques or processes, which may sometimes be referred to as randomtechniques or processes, generally refer to techniques which includefactors that are random, pseudo-random, or quasi-random. Examples ofstochastic factors, or random, factors, may include, but are notnecessarily limited to, pseudo-random number generators, Monte Carlosequences, and deterministic hashing.

Once stored in the portion of memory 124, the selected subset of lightsmay be used to render pixels in a depiction of the virtual scene.However, the process of selecting lights from the list of lights 122 maycause various impediments to efficient rendering. As noted, the lightselection process is at least partially random, and as such access tothe list of lights 122 may also be at least partially random, andinvolve access to widely separated regions of memory. The list 122 mayalso be very large, potentially include thousands, tens of thousands, oreven millions of lights. Accordingly, accessing the selected lightswithin the list can cause various inefficiencies, such as those thatinvolve memory access latency, cache coherence, cache utilization,thrashing, and so forth.

In at least one embodiment, a light refers to a virtual source ofillumination. In at least one embodiment, this may include sources whichemit or reflect light. A light may be associated with propertiesincluding a position of the light within a virtual scene and anintensity value. For example, a light may be associated with an x, y, zvalue indicating the light's position within the virtual scene, and avalue indicating how bright the light is. A light may also be associatedwith additional properties, such as parameters that describe intensity,color, diffusion pattern, and so forth. As used herein, the term lightgenerally refers to data which describes the light, such as thoserepresenting properties and parameters such as these.

In at least one embodiment, stages 110-118 of graphics pipeline 104utilize lights stored in the memory portion 124 to render portions ofthe virtual scene. In at least one embodiment, the computing device 102renders a frame of graphics by first randomly selecting a subset oflights from the list of lights 122 and storing the subset in the memoryportion 124. This is done, in at least one embodiment, prior torendering a frame. During rendering of the frame, the computing device102 renders a pixel by randomly selecting one or more lights from thememory portion 124. Note that the randomly sampling of lights refers tousing one or more stochastic processes to select lights from a pool oflights. A stochastic process includes, in at least one embodiment, anytechnique for selecting a light from a pool that incorporates at leastsome element of randomness, pseudo-randomness, or quasi-randomness. Inat least one embodiment, a stochastic process selects a light based onprobabilities that are proportional to the intensity of the light, suchthat brighter lights are more likely to be selected than dimmer lights.A pool of lights refers to lights that are candidates for selection.

FIG. 2 illustrates an example of a process of rendering a frame of avirtual scene by sampling from a list of scene lights and resamplingfrom memory portions, in accordance with at least one embodiment.

Although the example process 200 is depicted as a sequence ofoperations, it will be appreciated that, in embodiments, the depictedoperations may be altered in various ways, and that some operations maybe omitted, reordered, or performed in parallel with other operations,except where an order is explicitly stated or logically implied, such aswhen the input from one operation depends upon the output of anotheroperation.

The operations depicted by FIG. 2 may be performed by a system, such asthe system 100 depicted in FIG. 1 , comprising at least one processorand a memory with stored instructions that, in response to beingexecuted by the at least one processor, cause the system to perform thedepicted operations. In at least one embodiment, the operations areperformed by a combination of hardware and software, where said hardwareincludes one or more APUs, CPUs, GPUs, PPUs, GPGPUs, parallelprocessors, processing clusters, graphics processors, multiprocessors,and so forth as depicted by the various FIGS. herein. In at least oneembodiment, said software comprises libraries such as any of CUDA,OpenGL, OpenLC, ROCm, and may also include operating system software.

At 202, in at least one embodiment, the system builds a probabilitydensity function for one or more lights in the list of lights 122. In atleast one embodiment, the probability density function indicates alikelihood of selecting a given light. In at least one embodiment, theprobability density function incorporates the effects of variousparameters, such as light intensity, color, distance from a point to berendered, and so forth, so that some lights (e.g., those most likely tosignificantly contribute to lighting) are more likely to be selectedthan others.

In at least one embodiment, an alternative to a probability densityfunction is used. In at least one embodiment, lights are selectedrandomly, with equal odds of selecting a given light. In at least oneembodiment, a random number may, for such cases, be used to generate anindex into the list of lights. Various structures, such as trees orarrays, may be used to store the list, and may be used to facilitateselection of a light in conjunction with one or more stochasticprocesses, which may in some embodiments include the use of a randomnumber generator.

At 204, in at least one embodiment, the system selects a subset oflights from the list of lights. The lights, in at least one embodiment,are selected using one or more stochastic processes, such as those justdescribed in relation to a probability density function. The number oflights selected for the subset may vary, between embodiments, based onfactors such as the size of the portions to be rendered, the size ofmemory structures such as processor cache, and so forth. In at least oneembodiment, sets of lights, and subsets of those lights, are chosen sothat lighting information may be stored in one or more levels ofprocessor caches.

At 206, in at least one embodiment, the system stores the subset oflights in a memory portion. The memory portion may be a portion ofcomputer memory, such as a region of memory implemented by a randomaccess memory (“RAM”) device, or a region of virtual computer memory. Inat least one embodiment, the memory portion is a contiguous region ofphysical or virtual computer memory. In at least one embodiment, thememory portion is memory within a processor cache. In at least oneembodiment, reading or writing light information using a high-level datastructure, such as an array or linked list defined in a programminglanguage, will cause the subset of lights to be stored in a memoryportion. For example, reading light information from a portion of RAMmay cause the light information to also be stored in a cache memoryportion.

At 208, in at least one embodiment, the system selects and storesadditional subsets of lights. The number of subsets selected and loadedmay vary between embodiments. In at least one embodiment, subsets areselected and loaded into memory portions such that, during rendering ofa given frame, the subset can remain efficiently accessible (e.g.,in-cache) for as long as it is needed. A suitable number of subsets maygenerally be found through experimentation, or by consideration of thememory characteristics of the particular system on which the renderingis performed, and may further depend on variations of the algorithm usedto render pixels within the frame. For example, multiprocessor systemswith a plurality of caches may load a sufficient number of subsets suchthat each cache includes a memory portion with a subset of lights.

At 210, in at least one embodiment, a frame of graphics is renderedbased on lights resampled from the lights stored in the memory portion.In at least one embodiment, the frame is subdivided into tiles, and eachtile is rendered using one or more lights sampled from the memoryportion. In at least one embodiment, after these tiles are rendered, adifferent subset, loaded into a separate memory portion, is used torender other tiles. This process may then repeat until the entire frameis rendered.

FIG. 3 illustrates an example of a process for rendering a frame of avirtual scene by resampling from a memory portion, in accordance with atleast one embodiment. Although the example process 300 is depicted as asequence of operations, it will be appreciated that, in embodiments, thedepicted operations may be altered in various ways, and that someoperations may be omitted, reordered, or performed in parallel withother operations, except where an order is explicitly stated orlogically implied, such as when the input from one operation dependsupon the output of another operation.

The operations depicted by FIG. 3 may be performed by a system, such asthe system 100 depicted in FIG. 1 , comprising at least one processorand a memory with stored instructions that, in response to beingexecuted by the at least one processor, cause the system to perform thedepicted operations. In at least one embodiment, the operations areperformed by a combination of hardware and software, where said hardwareincludes one or more APUs, CPUs, GPUs, PPUs, GPGPUs, parallelprocessors, processing clusters, graphics processors, multiprocessors,and so forth as depicted by the various FIGS. herein. In at least oneembodiment, said software comprises libraries such as any of CUDA,OpenGL, OpenLC, ROCm, and may also include operating system software.

At 302, in at least one embodiment, the system performs pre-frameprocessing, including sampling lights from among the list of all scenelights, and storing sampled lights in one or more memory portions. In atleast one embodiment, the sampling is done from among less than allscene lights, but from some pool comprising a large number of lights,such that sampling from it results in performance issues due to issuessuch as inefficient usage of available processor cache memory. Forexample, in at least one embodiment, the pool might be small enough tofit in L3 cache, but too big to fit in more efficient L2 cache.

Pre-frame processing, in at least one embodiment, refers to processingdone prior to rendering an individual frame of a computer generatedscene depiction. As used herein, frame generally refers to one of aseries of frames generated to produce an animated sequence, but may alsobe used, in certain embodiments, to refer to single instances of acomputer-generated image.

At 304, in at least one embodiment, the system selects a tile to render.In at least one embodiment, a frame is subdivided into tiles, each ofwhich represents a portion of the frame. In at least one embodiment, thesize or number of tiles is based, at least in part, on factors which mayinclude the number of samples drawn from the list of lights, the numberof memory portions in which those samples are stored, the number ofprocessors, GPUs, and so forth that are available for rendering, thenumber of threads available, and so on.

At 306, in at least one embodiment, the system selects a memory portionfrom which it will resample lights. In at least one embodiment, this isdone by assigning a processor or thread of execution for rendering atile, configured such that the processor or thread draws samples fromthe selected memory portion.

At 308, in at least one embodiment, the system renders pixels that fallwithin the tile by sampling from the identified memory portion. Asdescribed in more detail herein, a pixel within a tile may be rendered,in at least one embodiment, by randomly resampling one or more lightsfrom the samples stored in the memory portion, and using the lightinformation stored in the memory portion to determine how to render thepixel. For example, the resampled lights may be used, in at least oneembodiment, to perform ray tracing.

At 310, in at least one embodiment, the system determines whether anyadditional tiles need to be rendered. If so, the operations described inrelation to elements 304 to 308 may be performed again. In at least oneembodiment, a new memory portion is used for each tile rendered. In atleast one embodiment, a given memory portion is reused among a first setof tiles, a new memory portion is selected for use with a second set,and so on. In at least one embodiment, multiple sets of tiles arerendered in parallel, and each may use, in at least one embodiment, adifferent memory portion.

At 312, in at least one embodiment, the system outputs the renderedframe. In at least one embodiment, this comprises providing data for thecompleted frame to another component within the system, such as acomponent that drives a display.

In at least one embodiment, rendering pixels near edges of a tile isadjusted by using additional stochastic factors, including random,pseudo-random, quasi-random factors, and/or determinative factors, toreduce or prevent artifacts in the rendered image. For example, adithering process may be used in conjunction with element 308 above, sothat for a pixel near a tile border, the set of memory portions fromwhich lights are selected is made to vary based on some randomizedelement or noise.

FIG. 4 illustrates an example of lights in a virtual area, in accordancewith at least one embodiment. In the example 400 of FIG. 4 , a virtualarea 402 is a three-dimensional area depicted from a top view and a sideview. A terrain 408 is included in the depicted example of a virtualarea 402, but a virtual area 402 can include or omit a variety offeatures, such as the depicted terrain 408, as well as other featuresnot depicted in the FIG., such as characters, obstacles, walls, andother objects.

In at least one embodiment, lights 410 are also included in the virtualarea 402, at various positions within the area 402. These lights 410emit illumination which may be factored into the rendering of acomputer-generated image based on the virtual area 402. There may bemany such lights 410, potentially numbering in the hundreds, thousands,or millions. Handling lights in these quantities may be challenging orimpractical with some approaches.

The FIG. 5 depicts an example of random selection of lights from a listof scene lights, in accordance with at least one embodiment. In theexample 500, a scene 506 comprises a number of scene lights 508. Theremay be a very large number of scene lights 508, such as hundreds,thousands, or millions of lights. These lights may be stored in memoryor storage as a list of scene lights 504.

In at least one embodiment, a list of scene lights 504 comprises one ormore arrays of memory in which information describing the scene lights508 is stored. For descriptive purposes, information describing a scenelight may be referred to herein as light information, light data, or asa light. In at least one embodiment, a list of scene lights comprises adata structure such as array, linked list, tree, B-Tree, and so forth. Alist of scene lights 504 may be stored in random access memory (“RAM”),on long-term storage such as a solid-state or mechanical disk drive, orin some other structure. It will be appreciated that these examples areintended to be illustrative, and as such should not be construed in amanner which would limit potential embodiments to only those thatincorporate the specific examples provided.

In at least one embodiment, sampled lights 502 are identified from thelist of scene lights 504 based on one or more processes that are atleast partially stochastic, which may include various random,quasi-random or pseudo-random factors. For example, in at least oneembodiment, the list of scene lights 504 has N lights stored in an arrayA with N storage locations. A stochastic process, in this exampleembodiment, may generate a random number between 0 and N−1 and obtainaccess to the light stored at A[N]. As depicted in the example 500, eachaccess may be to a different portion of the list of scene lights 504. Asdepicted in the example 500, each access to the list of scene lights 504may be in a different, random location. It will be appreciated thatthese examples are intended to be illustrative, and as such should notbe construed in a manner which would limit potential embodiments to onlythose that incorporate the specific examples provided.

In at least one embodiment, a ReSTIR algorithm relies on randomizationto generate images in which there are many lights, but in some casesthis randomization may lead to poor performance. However, as describedherein, the use of pre-randomization of samples may address theseperformance issues. For example, a techniques described herein uses aper-frame preprocessing technique to permute or perturb samplessufficiently to maintain (unbiased) image convergence. Thesepre-randomized samples, in at least one embodiment, are stored in a datastructure that can be accessed in a manner which avoids inefficientusage of cache memory. For example, by appropriate sizing, an array orother structure can be stored within a processor cache. Pre-randomizingsamples can provide efficiency gains by moving incoherent memoryaccesses to a pre-processing stage, rather than causing incoherentmemory accesses during per-pixel rendering. Additional performance canbe gained if this pre-processing stage is shorter or uses less memorythan other per-pixel candidate generation technique.

A rendering technique such as ReSTIR may use iterative applications ofresampled importance resampling (RIS) to decouple compute frequencies:

${\int{{f_{0}(x)}{f_{1}(x)}{f_{2}(x)}dx}} \approx {\frac{1}{N_{0}}{\sum\left\lbrack {{f_{0}\left( x_{i} \right)}\frac{1}{N_{1}}{\sum\left\lbrack {{f_{1}\left( x_{j} \right)}\frac{1}{N_{2}}{\sum\frac{f_{2}\left( x_{k} \right)}{p\left( x_{k} \right)}}} \right\rbrack}} \right\rbrack}}$

This pulls apart the integral ∫f₀(x)f₁(x)f₂(x)dx into a sum over termsevaluated at different frequencies. Some implementations of this maycause incoherence issues and poor performance. For example, inembodiments that employ techniques such as ReSTIR, incoherence issuesmay result from the samples x_(k) being distributed sparsely over a listthat may potentially be very long. However, in at least one embodiment,resampled importance sampling (“RIS”) may be applied again, prior toselecting the set of samples {x_(k)}, to reduce incoherence.

The techniques described herein may be further understood by examiningtwo degenerate forms of RIS. Assume a standard RIS estimator:

${\int{{f(x)}dx}} \approx {\frac{1}{N}{\sum\left\lbrack {\frac{f\left( x_{i} \right)}{\hat{p}\left( x_{i} \right)}\frac{1}{M}{\sum\frac{\hat{p}\left( x_{j} \right)}{q\left( x_{j} \right)}}} \right\rbrack}}$

And then examine the two degenerate cases, (i.e., {circumflex over(p)}(x)=f(x), and p(x)={circumflex over (p)}(x)):

${{\int{{f(x)}dx}} \approx {\frac{1}{N}{\sum\left\lbrack {\frac{f\left( x_{i} \right)}{f\left( x_{i} \right)}\frac{1}{M}{\sum\frac{f\left( x_{j} \right)}{p\left( x_{j} \right)}}} \right\rbrack}}} = {\frac{1}{N}{\sum\left\lbrack {\frac{1}{M}{\sum\frac{f\left( x_{j} \right)}{p\left( x_{j} \right)}}} \right\rbrack}}$${{\int{{f(x)}dx}} \approx {\frac{1}{N}{\sum\left\lbrack {\frac{f\left( x_{i} \right)}{\hat{p}\left( x_{i} \right)}\frac{1}{M}{\sum\frac{\hat{p}\left( x_{j} \right)}{\hat{p}\left( x_{j} \right)}}} \right\rbrack}}} = {\frac{1}{N}{\sum\left\lbrack {\frac{f\left( x_{i} \right)}{\overset{\hat{}}{p}\left( x_{i} \right)}\frac{1}{M}{\sum 1}} \right\rbrack}}$

The first appears to be like a stratified sampling, over random strata.In the second, RIS is still being applied, by first choosing M samples,then selecting a subset N of them. However, it gives the same estimatoras if sampling the N items directly. Note that the element

$\frac{1}{M}{\sum 1}$could be crossed out.

Again, a technique such as ReSTIR may take something like the followingform:

${\int{{f_{0}(x)}{f_{1}(x)}{f_{2}(x)}dx}} \approx {\frac{1}{N_{0}}{\sum\left\lbrack {{f_{0}\left( x_{i} \right)}\frac{1}{N_{1}}{\sum\left\lbrack {{f_{1}\left( x_{j} \right)}\frac{1}{N_{2}}{\sum\frac{f_{2}\left( x_{k} \right)}{p\left( x_{k} \right)}}} \right\rbrack}} \right\rbrack}}$

This uses an incoherent list of lights {L}, and samples it first into asmaller subset {x_(k)} of size N₂, then subsamples this set into an(even) smaller subset {x_(j)} of size N₁, then subsamples this into asubset {x_(i)} of size N₀.

In at least one embodiment, pre-randomization may still use samplesdistributed according to p(x), but from a smaller and more coherent setin memory:

${\int{{f_{0}(x)}{f_{1}(x)}{f_{2}(x)}dx}} \approx {\frac{1}{N_{0}}{\sum\left\lbrack {{f_{0}\left( x_{i} \right)}\frac{1}{N_{1}}{\sum\left\lbrack {{f_{1}\left( x_{j} \right)}\frac{1}{N_{2}}{\sum\left\lbrack {\frac{f_{2}\left( x_{k} \right)}{p\left( x_{k} \right)}\frac{1}{N_{3}}{\sum\frac{p\left( x_{l} \right)}{p\left( x_{l} \right)}}} \right\rbrack}} \right\rbrack}} \right\rbrack}}$

This subsamples {L} into four subsets: {L}→{x₁}→{x_(k)}→{x_(j)}→{x_(i)}.The inner sum is degenerate:

${\frac{1}{N_{3}}{\sum\frac{p\left( x_{l} \right)}{p\left( x_{l} \right)}}} \equiv 1$

In at least one embodiment, this numerical estimate:

${\int{{f_{0}(x)}{f_{1}(x)}{f_{2}(x)}dx}} \approx {\frac{1}{N_{0}}{\sum\left\lbrack {{f_{0}\left( x_{i} \right)}\frac{1}{N_{1}}{\sum\left\lbrack {{f_{1}\left( x_{j} \right)}\frac{1}{N_{2}}{\sum\left\lbrack {\frac{f_{2}\left( x_{k} \right)}{p\left( x_{k} \right)}\frac{1}{N_{3}}{\sum\frac{p\left( x_{l} \right)}{p\left( x_{l} \right)}}} \right\rbrack}} \right\rbrack}} \right\rbrack}}$may be computed by taking the domain {L}, where in at least oneembodiment {L} is a set of emissive triangles corresponding to the scenelights. In at least one embodiment, N₃ samples are then drawn from {L},according to the distribution p(x), to get {x_(l)}. Since insertion into{x_(l)} is according to p(x), samples in {x_(l)} are already distributedaccording to p(x). This means N₂ samples are drawn uniformly from{x_(i)} to get {x_(k)}. Then, embodiments continue to sample {x_(j)} and{x_(i)} from this set of samples {x_(k)}.

Forms of resampling may be classified as stratified and unstratified.The form with nested sums, as described above, is a stratified approach:

${\int{{f(x)}dx}} \approx {\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {\frac{f\left( x_{i} \right)}{\hat{p}\left( x_{i} \right)}\left( {\frac{1}{M}{\sum\limits_{j = 1}^{M}\frac{\hat{p}\left( x_{j} \right)}{p\left( x_{j} \right)}}} \right)} \right)}}$

This uses M*N candidates x_(ij).

The unstratified form can be formulated as:

${\int{{f(x)}{dx}}} \approx \left( {\frac{1}{N}{\sum\limits_{i = 1}^{N}\left( {\frac{f\left( x_{i} \right)}{\hat{p}\left( x_{i} \right)}\left( {\frac{1}{M}{\sum\limits_{j = 1}^{M}\frac{\hat{p}\left( x_{j} \right)}{p\left( x_{j} \right)}}} \right)} \right)}} \right.$This may only require M candidates x_(j) and can reuse these candidatesto draw all N samples. In this pre-randomized form of RIS:

${{\int{{f_{0}(x)}{f_{1}(x)}{f_{2}(x)}dx}} \approx {\frac{1}{N_{0}}{\sum\left\lbrack {{f_{0}\left( x_{i} \right)}\frac{1}{N_{1}}{\sum\left\lbrack {{f_{1}\left( x_{j} \right)}\frac{1}{N_{2}}{\sum\left\lbrack {\frac{f_{2}\left( x_{k} \right)}{p\left( x_{k} \right)}\frac{1}{N_{3}}{\sum\frac{p\left( x_{l} \right)}{p\left( x_{l} \right)}}} \right\rbrack}} \right\rbrack}} \right\rbrack}}},$the pre-randomized set can actually be pulled out of the sum, if it isacceptable to give up some degree of stratification:

${\int{{f_{0}(x)}{f_{1}(x)}{f_{2}(x)}dx}} \approx {\left( {\frac{1}{N_{0}}{\sum\left\lbrack {{f_{0}\left( x_{i} \right)}\frac{1}{N_{1}}{\sum\left\lbrack {{f_{1}\left( x_{j} \right)}\frac{1}{N_{2}}{\sum\frac{f_{2}\left( x_{k} \right)}{p\left( x_{k} \right)}}} \right\rbrack}} \right\rbrack}} \right){\left( {\frac{1}{N_{3}}{\sum\frac{p\left( x_{l} \right)}{p\left( x_{l} \right)}}} \right).}}$

Since this was stratification that wouldn't be the case without theextra set of N₃ samples {x_(l)}, this may not be a significant factor insome embodiments.

In at least one embodiment, there can also be partial stratification,using multiple sets {x_(l)} yet using fewer than the number necessaryfor full stratification (in this case, that would be N₀N₁N₂ differentsets {x_(l)}). And the degenerate term

$\frac{1}{N_{3}}{\sum\frac{p\left( x_{l} \right)}{p\left( x_{l} \right)}}$cancels away, no matter where it is put, indicating flexibility. Variousembodiments may be based on how this “partial stratification” occurs invarious pre-randomization algorithms, as described herein.

In an example embodiment, a pre-randomization stage and a render-timestage is performed. An example illustration of such an algorithm isdepicted in FIG. 11 .

A pre-randomization stage may comprise 1) Input a list of light samplesL, a number of subsets S_(i)={x_(l)} to generate, and a size K for eachsubset; and 2) For each of the S_(i) subsets, draw K lights from Laccording the “initial light candidate” probability density functionp(x). For example, p(x)∝L_(e)(x), i.e., each light's emitted power.

At a render-time stage, for each pixel, Instead of drawing M samplesfrom the total list of light samples {L} using distribution p(x), Msamples are drawn uniformly from one of the pre-randomized light subsetsS_(i)={x_(l)}. This uniform sampling can be done in a stratified andinterleaved manner to ensure traversal of S_(i) is maximally coherent.

FIG. 6 depicts an example of rendering tiles based on a selection of oneor more pre-sampled subsets of lights, in accordance with at least oneembodiment. As depicted by the example 600, a frame 602 may besubdivided into tiles, and each tile may be rendered separately. In atleast one embodiment, a plurality of subsets of lights are generatedduring pre-frame processing. In at least one embodiment, each subset isstored in a separate data structure or memory portion. An embodiment ofa rendering algorithm may incorporate a step in which a subset of lightsis selected for use in rendering a tile. During rendering, each pixelresamples from some subset S_(i) of the original light list {L}. Toensure warp coherence, active threads sharing processor cache or othermemory resources should resample from the same subset S_(i).

All pixels in some image tile may sample from the same S_(i). Forexample, in the example 600, all pixels from a first tile 604 arerendered based on pixels resampled from the subset S₁, pixels from asecond tile 606 are rendered using pixels resampled from S₂, pixels froma third tile 608 are rendered using pixels resampled from S₃, and pixelsfrom a fourth tile 610 are rendered using pixels resampled from S₄.

In at least one embodiment, target tile size is configured based onhardware configuration. Experiments have shown that, in someembodiments, 8×8 and 16×16 tiles may result in good performance. Inthese embodiments, larger tiles introduced artifacts, while using 4×4image tiles increased incoherence and thereby reduced performance.

FIG. 7 is an illustration of a possible approach to candidate selectionfor a sampling technique such as ReSTIR. In the example 700, a gatherapproach is used. As depicted in the example 700, a frame 702 consistsof various pixels 706, 708 that are each rendered based on a subset oflights drawn randomly from a list of lights 402. In this example, it isassumed that the subset is identified prior to rendering the frame, andre-used for various pixels within the frame 702. To render a pixel 706,thirty two reads, from #1 to #32, are performed from the list of lights704, to obtain information from lights 710 in the identified subset, butstored in the list of lights 704 comprising all scene lights (in thisexample, four million scene lights). Subsequently, when another pixel708 is rendered, using the same subset of lights, the system may againperform reads #1 to #32 to access the same subset of lights from thelist of lights 704. However, because other pixels may have been renderedusing different lights (e.g., lights from another subset), the lightsfrom the original subset are no longer in cache. As such, this approachthat may have problematic performance characteristics.

FIG. 8 is an illustration of ReSTIR candidate selection using a scatterapproach, in accordance with at least one embodiment. As describedherein, lights can be pre-randomized into “subpools” S_(i), asvisualized in the example 800. In addition, the example 800 also showsthat embodiments may vary how subpools get distributed over the screen.In at least one embodiment, a screen tile may grab from one subpool orfrom multiple subpools. In at least one embodiment, this is defined byreuse parameters. For example, in at least one embodiment, each light ina subpool is reused some predetermined number of times, as indicated bya reuse parameter. In at least one embodiment, tile size variesdynamically based on the indicated reuse parameters.

In at least one embodiment, one or more subsets of lights 804 isgenerated from a list of all scene lights. The list of all scene lightsmay be very large, such as, in one example, four million lights. Thenumber and size of the one or more subsets of lights 804 may varydepending on configuration. In one example, the one or more subsets oflights comprises multiple subpools each including 1024 lights.

In at least one embodiment, the one or more subsets of lights 804 aregenerated by sampling or shuffling lights 810 from among all scenelights. In at least one embodiment, one or more stochastic processes,such as random number generation, are used in the sampling or shuffling.

In at least one embodiment, some or all of the one or more subsets arestored in a memory portion 812. For example, in at least one embodiment,a subpool comprising 1024 lights is stored, as depicted in FIG. 8 , in amemory portion 812. This subpool may then be used to render pixelswithin various tiles 806, 808 of frame 802, by drawing pre-randomizedsamples from the subpool in the memory portion 812.

In at least one embodiment, this pre-randomization approach providesvarious advantages. For example, if care is taken to promote consistentstatistical distribution of light samples in subpools S_(i) . . . ,there can be flexibility regarding how the subpools are created. Thesubpools may, for example, be created in cheaper ways such as shufflingbetween light subpools, as depicted in FIG. 9 . This avoids incoherentmemory reads into the global light list {L} (in this example, 4 millionentries long).

FIG. 9 is an illustration of subpool reshuffling, in accordance with atleast one embodiment. In at least one embodiment, multiple subpools904-908 are loaded into one or more memory portions, such as one or moreportions of L1/L2/DRAM 910. These subpools may be read, at steps 1A, 1B,and 1C, and used to render tiles of a frame. At steps 2A and 2B, lightsin the subpools 904, 906, 908 are shuffled. For example, in at least oneembodiment, some of the lights in a subpool 904 are swapped, based onone or more stochastic processes, with some of the lights in anothersubpool 906. As depicted in the example 900, the shuffling may occurover time. In at least one embodiment, reads and write-back operationsto L1/L2/DRAM 910 may overlap, as depicted by the overlapping of readsteps 1A, 1B, 1C and write steps 3A, 3B, 3C, along a timeline 902.

FIG. 10 is an illustration 1000 of rendering a frame using multipleopened tiles, in accordance with at least one embodiment. An opened tilemay refer to tiles for which at least one subset of lights has beensampled from among a larger number of scene lights. This subset is madeavailable for use in rendering by having been loaded into a memoryportion separate from the memory or storage in which the scene lightsare kept. When multiple tiles are open, they may share a single subpoolor, alternatively, rely on multiple subpools that have been loaded intoa memory portion.

In at least one embodiment, multiple tiles are opened at once and thereis cycling between multiple subpools. For example, as depicted in FIG.10 , a frame 1002 may be divided into T=16 tiles, of 2×2 pixel per tile,1006, 1008, using four samples per pixel. A current subpool might thenbe used for one sample from each of the T=16 tiles. In this example, itwould take 16 subpools loaded into memory portion 1012 to finish all 16tiles, because each tile uses 2×2×4=16 samples. In at least oneembodiment, each subpool services two samples per pixel, thereby using32 subpools. In at least one embodiment, the number of tiles isincreased to T=32, also using 32 subpools. It will be appreciated thatthese examples are intended to be illustrative, and as such should notbe construed in a manner which would limit the scope of potentialembodiments to only those that incorporate the specific examplesprovided. These parameters may be adjusted, in various embodiments, tovalues that best utilize available hardware. In general, suitable valuesmay be determined through experimentation and consideration of hardwarecharacteristics, potentially including the sizes of processor caches,such as L1, L2, and L3 processor caches.

In at least one embodiment, the pre-randomization techniques describedherein provide various additional advantages. Sampling lights can be anexpensive operation, especially with a heterogeneous set of light types,such as emissive triangles, spheres, meshes, planes, cylinders, and soforth. Control flow divergence on SIMD processors can also be asignificant cause or performance slowdown. By pre-randomization, thisexpensive divergence is moved outside the performance-sensitive innerrendering loop. Instead it occurs before rendering, many fewer times perframe. Different light types may be split into different light poolsS_(i), or lights may be sampled using a coherent SIMD control flows,then randomized into subpools as a second step.

In at least one embodiment, the pre-randomization techniques describedherein increase efficiency in handling dynamic lights. When lights movearound the scene and change intensity, there may be a need to update thecurrent positions of the lights, update the intensity of the lights, andpotentially update the sampling distribution used to select the lights.By pre-randomizing lights, these updates can be done over a fewer numberof lights. For example, in at least one embodiment, only those insidelights that are in the frame's selected subpools S_(i) are fullyupdated.

In at least one embodiment, the pre-randomization techniques describedherein increase allow greater flexibility. For example, the use of tilesallows flexibly changing the shape and domain of the light sampling.

FIG. 11 is an illustration of an example process comprisingpre-randomization and render-time stages, in accordance with at leastone embodiment. Although the example process 1100 is depicted as asequence of operations, it will be appreciated that, in embodiments, thedepicted operations may be altered in various ways, and that someoperations may be omitted, reordered, or performed in parallel withother operations, except where an order is explicitly stated orlogically implied, such as when the input from one operation dependsupon the output of another operation.

The operations depicted by FIG. 11 may be performed by a system, such asthe system 100 depicted in FIG. 1 , comprising at least one processorand a memory with stored instructions that, in response to beingexecuted by the at least one processor, cause the system to perform thedepicted operations. In at least one embodiment, the operations areperformed by a combination of hardware and software, where said hardwareincludes one or more APUs, CPUs, GPUs, PPUs, GPGPUs, parallelprocessors, processing clusters, graphics processors, multiprocessors,and so forth as depicted by the various FIGS. herein. In at least oneembodiment, said software comprises libraries such as any of CUDA,OpenGL, OpenLC, ROCm, and may also include operating system software.

At 1102, in at least one embodiment, the system receives a list of lightsamples L, a number of subsets S_(i)={x_(i)} to be generated, and a sizeK for each subset.

At 1104, in at least one embodiment, the system draws, for each of theS_(i) subsets, K lights from L according to an initial light candidateprobability function p(x).

In at least one embodiment, the preceding operations 1102, 1104 areperformed during a pre-randomization stage 1110 in which the subsetsS_(i) are drawn from the list of lights L. During second render-timestage 1112 comprising operations 1106 and 1108, the subsets are used torender a frame of graphics.

At 1106, in at least one embodiment, the system draws M samplesuniformly from one of the pre-randomized light subsets S_(i)={x_(i)}. Asillustrated in 1108, the system may perform the uniform sampling in astratified and interleaved manner to improve cache coherence during thetraversal of S_(i). FIG. 9 depicts an example of sampling performed in astratified and interleaved manner.

Light subpools may be associated with specific groups of pixels, texels,or voxels. Light subpools may be used to select even smaller subpools.This may correspond to a hierarchical reduction in incoherence,essentially building a stochastic data structure from random,pseudo-random, or quasi-random selection of lights. In at least oneembodiment, this stochastic data structure comprises hierarchical levelsof samples, with each level comprising samples selected, by processesthat are at least partially random, from the level below it. Lightsubpools may be resized dynamically for performance and qualitytradeoffs, if using subpools and screen tiles leads to banding artifactsin certain cases. The number and size of subpools may be varied acrossuser devices to control performance, memory usage, and quality over avariety of hardware types of varying capability.

Data Center

FIG. 12 illustrates an exemplary data center 1200, in accordance with atleast one embodiment. In at least one embodiment, data center 1200includes, without limitation, a data center infrastructure layer 1210, aframework layer 1220, a software layer 1230 and an application layer1240.

In at least one embodiment, as shown in FIG. 12 , data centerinfrastructure layer 1210 may include a resource orchestrator 1212,grouped computing resources 1214, and node computing resources (“nodeC.R.s”) 1216(1)-1216(N), where “N” represents any whole, positiveinteger. In at least one embodiment, node C.R.s 1216(1)-1216(N) mayinclude, but are not limited to, any number of central processing units(“CPUs”) or other processors (including accelerators, field programmablegate arrays (“FPGAs”), graphics processors, etc.), memory devices (e.g.,dynamic read-only memory), storage devices (e.g., solid state or diskdrives), network input/output (“NW I/O”) devices, network switches,virtual machines (“VMs”), power modules, and cooling modules, etc. In atleast one embodiment, one or more node C.R.s from among node C.R.s1216(1)-1216(N) may be a server having one or more of above-mentionedcomputing resources.

In at least one embodiment, grouped computing resources 1214 may includeseparate groupings of node C.R.s housed within one or more racks (notshown), or many racks housed in data centers at various geographicallocations (also not shown). Separate groupings of node C.R.s withingrouped computing resources 1214 may include grouped compute, network,memory or storage resources that may be configured or allocated tosupport one or more workloads. In at least one embodiment, several nodeC.R.s including CPUs or processors may grouped within one or more racksto provide compute resources to support one or more workloads. In atleast one embodiment, one or more racks may also include any number ofpower modules, cooling modules, and network switches, in anycombination.

In at least one embodiment, resource orchestrator 1212 may configure orotherwise control one or more node C.R.s 1216(1)-1216(N) and/or groupedcomputing resources 1214. In at least one embodiment, resourceorchestrator 1212 may include a software design infrastructure (“SDI”)management entity for data center 1200. In at least one embodiment,resource orchestrator 1212 may include hardware, software or somecombination thereof.

In at least one embodiment, as shown in FIG. 12 , framework layer 1220includes, without limitation, a job scheduler 1232, a configurationmanager 1234, a resource manager 1236 and a distributed file system1238. In at least one embodiment, framework layer 1220 may include aframework to support software 1252 of software layer 1230 and/or one ormore application(s) 1242 of application layer 1240. In at least oneembodiment, software 1252 or application(s) 1242 may respectivelyinclude web-based service software or applications, such as thoseprovided by Amazon Web Services, Google Cloud and Microsoft Azure. In atleast one embodiment, framework layer 1220 may be, but is not limitedto, a type of free and open-source software web application frameworksuch as Apache Spark™ (hereinafter “Spark”) that may utilize distributedfile system 1238 for large-scale data processing (e.g., “big data”). Inat least one embodiment, job scheduler 1232 may include a Spark driverto facilitate scheduling of workloads supported by various layers ofdata center 1200. In at least one embodiment, configuration manager 1234may be capable of configuring different layers such as software layer1230 and framework layer 1220, including Spark and distributed filesystem 1238 for supporting large-scale data processing. In at least oneembodiment, resource manager 1236 may be capable of managing clusteredor grouped computing resources mapped to or allocated for support ofdistributed file system 1238 and job scheduler 1232. In at least oneembodiment, clustered or grouped computing resources may include groupedcomputing resource 1214 at data center infrastructure layer 1210. In atleast one embodiment, resource manager 1236 may coordinate with resourceorchestrator 1212 to manage these mapped or allocated computingresources.

In at least one embodiment, software 1252 included in software layer1230 may include software used by at least portions of node C.R.s1216(1)-1216(N), grouped computing resources 1214, and/or distributedfile system 1238 of framework layer 1220. One or more types of softwaremay include, but are not limited to, Internet web page search software,e-mail virus scan software, database software, and streaming videocontent software.

In at least one embodiment, application(s) 1242 included in applicationlayer 1240 may include one or more types of applications used by atleast portions of node C.R.s 1216(1)-1216(N), grouped computingresources 1214, and/or distributed file system 1238 of framework layer1220. In at least one or more types of applications may include, withoutlimitation, CUDA applications.

In at least one embodiment, any of configuration manager 1234, resourcemanager 1236, and resource orchestrator 1212 may implement any numberand type of self-modifying actions based on any amount and type of dataacquired in any technically feasible fashion. In at least oneembodiment, self-modifying actions may relieve a data center operator ofdata center 1200 from making possibly bad configuration decisions andpossibly avoiding underutilized and/or poor performing portions of adata center.

Computer-Based Systems

The following FIGS. set forth, without limitation, exemplarycomputer-based systems that can be used to implement at least oneembodiment.

FIG. 13 illustrates a processing system 1300, in accordance with atleast one embodiment. In at least one embodiment, processing system 1300includes one or more processors 1302 and one or more graphics processors1308, and may be a single processor desktop system, a multiprocessorworkstation system, or a server system having a large number ofprocessors 1302 or processor cores 1307. In at least one embodiment,processing system 1300 is a processing platform incorporated within asystem-on-a-chip (“Sort”) integrated circuit for use in mobile,handheld, or embedded devices.

In at least one embodiment, processing system 1300 can include, or beincorporated within a server-based gaming platform, a game console, amedia console, a mobile gaming console, a handheld game console, or anonline game console. In at least one embodiment, processing system 1300is a mobile phone, smart phone, tablet computing device or mobileInternet device. In at least one embodiment, processing system 1300 canalso include, couple with, or be integrated within a wearable device,such as a smart watch wearable device, smart eyewear device, augmentedreality device, or virtual reality device. In at least one embodiment,processing system 1300 is a television or set top box device having oneor more processors 1302 and a graphical interface generated by one ormore graphics processors 1308.

In at least one embodiment, one or more processors 1302 each include oneor more processor cores 1307 to process instructions which, whenexecuted, perform operations for system and user software. In at leastone embodiment, each of one or more processor cores 1307 is configuredto process a specific instruction set 1309. In at least one embodiment,instruction set 1309 may facilitate Complex Instruction Set Computing(“CISC”), Reduced Instruction Set Computing (“RISC”), or computing via aVery Long Instruction Word (“VLIW”). In at least one embodiment,processor cores 1307 may each process a different instruction set 1309,which may include instructions to facilitate emulation of otherinstruction sets. In at least one embodiment, processor core 1307 mayalso include other processing devices, such as a digital signalprocessor (“DSP”).

In at least one embodiment, processor 1302 includes cache memory(‘cache”) 1304. In at least one embodiment, processor 1302 can have asingle internal cache or multiple levels of internal cache. In at leastone embodiment, cache memory is shared among various components ofprocessor 1302. In at least one embodiment, processor 1302 also uses anexternal cache (e.g., a Level 3 (“L3”) cache or Last Level Cache(“LLC”)) (not shown), which may be shared among processor cores 1307using known cache coherency techniques. In at least one embodiment,register file 1306 is additionally included in processor 1302 which mayinclude different types of registers for storing different types of data(e.g., integer registers, floating point registers, status registers,and an instruction pointer register). In at least one embodiment,register file 1306 may include general-purpose registers or otherregisters.

In at least one embodiment, one or more processor(s) 1302 are coupledwith one or more interface bus(es) 1310 to transmit communicationsignals such as address, data, or control signals between processor 1302and other components in processing system 1300. In at least oneembodiment interface bus 1310, in one embodiment, can be a processorbus, such as a version of a Direct Media Interface (“DMI”) bus. In atleast one embodiment, interface bus 1310 is not limited to a DMI bus,and may include one or more Peripheral Component Interconnect buses(e.g., “PCI,” PCI Express (“PCIe”)), memory buses, or other types ofinterface buses. In at least one embodiment processor(s) 1302 include anintegrated memory controller 1316 and a platform controller hub 1330. Inat least one embodiment, memory controller 1316 facilitatescommunication between a memory device and other components of processingsystem 1300, while platform controller hub (“PCH”) 1330 providesconnections to Input/Output (“I/O”) devices via a local I/O bus.

In at least one embodiment, memory device 1320 can be a dynamic randomaccess memory (“DRAM”) device, a static random access memory (“SRAM”)device, flash memory device, phase-change memory device, or some othermemory device having suitable performance to serve as processor memory.In at least one embodiment memory device 1320 can operate as systemmemory for processing system 1300, to store data 1322 and instructions1321 for use when one or more processors 1302 executes an application orprocess. In at least one embodiment, memory controller 1316 also coupleswith an optional external graphics processor 1312, which may communicatewith one or more graphics processors 1308 in processors 1302 to performgraphics and media operations. In at least one embodiment, a displaydevice 1311 can connect to processor(s) 1302. In at least one embodimentdisplay device 1311 can include one or more of an internal displaydevice, as in a mobile electronic device or a laptop device or anexternal display device attached via a display interface (e.g.,DisplayPort, etc.). In at least one embodiment, display device 1311 caninclude a head mounted display (“HMD”) such as a stereoscopic displaydevice for use in virtual reality (“VR”) applications or augmentedreality (“AR”) applications.

In at least one embodiment, platform controller hub 1330 enablesperipherals to connect to memory device 1320 and processor 1302 via ahigh-speed I/O bus. In at least one embodiment, I/O peripherals include,but are not limited to, an audio controller 1346, a network controller1334, a firmware interface 1328, a wireless transceiver 1326, touchsensors 1325, a data storage device 1324 (e.g., hard disk drive, flashmemory, etc.). In at least one embodiment, data storage device 1324 canconnect via a storage interface (e.g., SATA) or via a peripheral bus,such as PCI, or PCIe. In at least one embodiment, touch sensors 1325 caninclude touch screen sensors, pressure sensors, or fingerprint sensors.In at least one embodiment, wireless transceiver 1326 can be a Wi-Fitransceiver, a Bluetooth transceiver, or a mobile network transceiversuch as a 3G, 4G, or Long Term Evolution (“LTE”) transceiver. In atleast one embodiment, firmware interface 1328 enables communication withsystem firmware, and can be, for example, a unified extensible firmwareinterface (“UEFI”). In at least one embodiment, network controller 1334can enable a network connection to a wired network. In at least oneembodiment, a high-performance network controller (not shown) coupleswith interface bus 1310. In at least one embodiment, audio controller1346 is a multi-channel high definition audio controller. In at leastone embodiment, processing system 1300 includes an optional legacy I/Ocontroller 1340 for coupling legacy (e.g., Personal System 2 (“PS/2”))devices to processing system 1300. In at least one embodiment, platformcontroller hub 1330 can also connect to one or more Universal Serial Bus(“USB”) controllers 1342 connect input devices, such as keyboard andmouse 1343 combinations, a camera 1344, or other USB input devices.

In at least one embodiment, an instance of memory controller 1316 andplatform controller hub 1330 may be integrated into a discreet externalgraphics processor, such as external graphics processor 1312. In atleast one embodiment, platform controller hub 1330 and/or memorycontroller 1316 may be external to one or more processor(s) 1302. Forexample, in at least one embodiment, processing system 1300 can includean external memory controller 1316 and platform controller hub 1330,which may be configured as a memory controller hub and peripheralcontroller hub within a system chipset that is in communication withprocessor(s) 1302.

FIG. 14 illustrates a computer system 1400, in accordance with at leastone embodiment. In at least one embodiment, computer system 1400 may bea system with interconnected devices and components, an SOC, or somecombination. In at least on embodiment, computer system 1400 is formedwith a processor 1402 that may include execution units to execute aninstruction. In at least one embodiment, computer system 1400 mayinclude, without limitation, a component, such as processor 1402 toemploy execution units including logic to perform algorithms forprocessing data. In at least one embodiment, computer system 1400 mayinclude processors, such as PENTIUM® Processor family, Xeon™, Itanium®,XScale™ and/or StrongARM™, Intel® Core™, or Intel® Nervana™microprocessors available from Intel Corporation of Santa Clara, Calif.,although other systems (including PCs having other microprocessors,engineering workstations, set-top boxes and like) may also be used. Inat least one embodiment, computer system 1400 may execute a version ofWINDOWS' operating system available from Microsoft Corporation ofRedmond, Wash., although other operating systems (UNIX and Linux forexample), embedded software, and/or graphical user interfaces, may alsobe used.

In at least one embodiment, computer system 1400 may be used in otherdevices such as handheld devices and embedded applications. Someexamples of handheld devices include cellular phones, Internet Protocoldevices, digital cameras, personal digital assistants (“PDAs”), andhandheld PCs. In at least one embodiment, embedded applications mayinclude a microcontroller, a digital signal processor (DSP), an SoC,network computers (“NetPCs”), set-top boxes, network hubs, wide areanetwork (“WAN”) switches, or any other system that may perform one ormore instructions.

In at least one embodiment, computer system 1400 may include, withoutlimitation, processor 1402 that may include, without limitation, one ormore execution units 1408 that may be configured to execute a ComputeUnified Device Architecture (“CUDA”) (CUDA® is developed by NVIDIACorporation of Santa Clara, Calif.) program. In at least one embodiment,a CUDA program is at least a portion of a software application writtenin a CUDA programming language. In at least one embodiment, computersystem 1400 is a single processor desktop or server system. In at leastone embodiment, computer system 1400 may be a multiprocessor system. Inat least one embodiment, processor 1402 may include, without limitation,a CISC microprocessor, a RISC microprocessor, a VLIW microprocessor, aprocessor implementing a combination of instruction sets, or any otherprocessor device, such as a digital signal processor, for example. In atleast one embodiment, processor 1402 may be coupled to a processor bus1410 that may transmit data signals between processor 1402 and othercomponents in computer system 1400.

In at least one embodiment, processor 1402 may include, withoutlimitation, a Level 1 (“L1”) internal cache memory (“cache”) 1404. In atleast one embodiment, processor 1402 may have a single internal cache ormultiple levels of internal cache. In at least one embodiment, cachememory may reside external to processor 1402. In at least oneembodiment, processor 1402 may also include a combination of bothinternal and external caches. In at least one embodiment, a registerfile 1406 may store different types of data in various registersincluding, without limitation, integer registers, floating pointregisters, status registers, and instruction pointer register.

In at least one embodiment, execution unit 1408, including, withoutlimitation, logic to perform integer and floating point operations, alsoresides in processor 1402. Processor 1402 may also include a microcode(“ucode”) read only memory (“ROM”) that stores microcode for certainmacro instructions. In at least one embodiment, execution unit 1408 mayinclude logic to handle a packed instruction set 1409. In at least oneembodiment, by including packed instruction set 1409 in an instructionset of a general-purpose processor 1402, along with associated circuitryto execute instructions, operations used by many multimedia applicationsmay be performed using packed data in a general-purpose processor 1402.In at least one embodiment, many multimedia applications may beaccelerated and executed more efficiently by using full width of aprocessor's data bus for performing operations on packed data, which mayeliminate a need to transfer smaller units of data across a processor'sdata bus to perform one or more operations one data element at a time.

In at least one embodiment, execution unit 1408 may also be used inmicrocontrollers, embedded processors, graphics devices, DSPs, and othertypes of logic circuits. In at least one embodiment, computer system1400 may include, without limitation, a memory 1420. In at least oneembodiment, memory 1420 may be implemented as a DRAM device, an SRAMdevice, flash memory device, or other memory device. Memory 1420 maystore instruction(s) 1419 and/or data 1421 represented by data signalsthat may be executed by processor 1402.

In at least one embodiment, a system logic chip may be coupled toprocessor bus 1410 and memory 1420. In at least one embodiment, thesystem logic chip may include, without limitation, a memory controllerhub (“MCH”) 1416, and processor 1402 may communicate with MCH 1416 viaprocessor bus 1410. In at least one embodiment, MCH 1416 may provide ahigh bandwidth memory path 1418 to memory 1420 for instruction and datastorage and for storage of graphics commands, data and textures. In atleast one embodiment, MCH 1416 may direct data signals between processor1402, memory 1420, and other components in computer system 1400 and tobridge data signals between processor bus 1410, memory 1420, and asystem I/O 1422. In at least one embodiment, system logic chip mayprovide a graphics port for coupling to a graphics controller. In atleast one embodiment, MCH 1416 may be coupled to memory 1420 throughhigh bandwidth memory path 1418 and graphics/video card 1412 may becoupled to MCH 1416 through an Accelerated Graphics Port (“AGP”)interconnect 1414.

In at least one embodiment, computer system 1400 may use system I/O 1422that is a proprietary hub interface bus to couple MCH 1416 to I/Ocontroller hub (“ICH”) 1430. In at least one embodiment, ICH 1430 mayprovide direct connections to some I/O devices via a local I/O bus. Inat least one embodiment, local I/O bus may include, without limitation,a high-speed I/O bus for connecting peripherals to memory 1420, achipset, and processor 1402. Examples may include, without limitation,an audio controller 1429, a firmware hub (“flash BIOS”) 1428, a wirelesstransceiver 1426, a data storage 1424, a legacy I/O controller 1423containing a user input interface 1425 and a keyboard interface, aserial expansion port 1427, such as a USB, and a network controller1434. Data storage 1424 may comprise a hard disk drive, a floppy diskdrive, a CD-ROM device, a flash memory device, or other mass storagedevice.

In at least one embodiment, FIG. 14 illustrates a system, which includesinterconnected hardware devices or “chips.” In at least one embodiment,FIG. 14 may illustrate an exemplary SoC. In at least one embodiment,devices illustrated in FIG. 14 may be interconnected with proprietaryinterconnects, standardized interconnects (e.g., PCIe), or somecombination thereof. In at least one embodiment, one or more componentsof system 1400 are interconnected using compute express link (“CXL”)interconnects.

FIG. 15 illustrates a system 1500, in accordance with at least oneembodiment. In at least one embodiment, system 1500 is an electronicdevice that utilizes a processor 1510. In at least one embodiment,system 1500 may be, for example and without limitation, a notebook, atower server, a rack server, a blade server, a laptop, a desktop, atablet, a mobile device, a phone, an embedded computer, or any othersuitable electronic device.

In at least one embodiment, system 1500 may include, without limitation,processor 1510 communicatively coupled to any suitable number or kind ofcomponents, peripherals, modules, or devices. In at least oneembodiment, processor 1510 is coupled using a bus or interface, such asan I²C bus, a System Management Bus (“SMBus”), a Low Pin Count (“LPC”)bus, a Serial Peripheral Interface (“SPI”), a High Definition Audio(“HDA”) bus, a Serial Advance Technology Attachment (“SATA”) bus, a USB(versions 1, 2, 3), or a Universal Asynchronous Receiver/Transmitter(“UART”) bus. In at least one embodiment, FIG. 15 illustrates a systemwhich includes interconnected hardware devices or “chips.” In at leastone embodiment, FIG. 15 may illustrate an exemplary SoC. In at least oneembodiment, devices illustrated in FIG. 15 may be interconnected withproprietary interconnects, standardized interconnects (e.g., PCIe) orsome combination thereof. In at least one embodiment, one or morecomponents of FIG. 15 are interconnected using CXL interconnects.

In at least one embodiment, FIG. 15 may include a display 1524, a touchscreen 1525, a touch pad 1530, a Near Field Communications unit (“NFC”)1545, a sensor hub 1540, a thermal sensor 1546, an Express Chipset(“EC”) 1535, a Trusted Platform Module (“TPM”) 1538, BIOS/firmware/flashmemory (“BIOS, FW Flash”) 1522, a DSP 1560, a Solid State Disk (“SSD”)or Hard Disk Drive (“HDD”) 1520, a wireless local area network unit(“WLAN”) 1550, a Bluetooth unit 1552, a Wireless Wide Area Network unit(“WWAN”) 1556, a Global Positioning System (“GPS”) 1555, a camera (“USB3.0 camera”) 1554 such as a USB 3.0 camera, or a Low Power Double DataRate (“LPDDR”) memory unit (“LPDDR3”) 1515 implemented in, for example,LPDDR3 standard. These components may each be implemented in anysuitable manner.

In at least one embodiment, other components may be communicativelycoupled to processor 1510 through components discussed above. In atleast one embodiment, an accelerometer 1541, an Ambient Light Sensor(“ALS”) 1542, a compass 1543, and a gyroscope 1544 may becommunicatively coupled to sensor hub 1540. In at least one embodiment,a thermal sensor 1539, a fan 1537, a keyboard 1536, and a touch pad 1530may be communicatively coupled to EC 1535. In at least one embodiment, aspeaker 1563, a headphones 1564, and a microphone (“mic”) 1565 may becommunicatively coupled to an audio unit (“audio codec and class d amp”)1562, which may in turn be communicatively coupled to DSP 1560. In atleast one embodiment, audio unit 1562 may include, for example andwithout limitation, an audio coder/decoder (“codec”) and a class Damplifier. In at least one embodiment, a SIM card (“SIM”) 1557 may becommunicatively coupled to WWAN unit 1556. In at least one embodiment,components such as WLAN unit 1550 and Bluetooth unit 1552, as well asWWAN unit 1556 may be implemented in a Next Generation Form Factor(“NGFF”).

FIG. 16 illustrates an exemplary integrated circuit 1600, in accordancewith at least one embodiment. In at least one embodiment, exemplaryintegrated circuit 1600 is an SoC that may be fabricated using one ormore IP cores. In at least one embodiment, integrated circuit 1600includes one or more application processor(s) 1605 CPUs), at least onegraphics processor 1610, and may additionally include an image processor1615 and/or a video processor 1620, any of which may be a modular IPcore. In at least one embodiment, integrated circuit 1600 includesperipheral or bus logic including a USB controller 1625, a UARTcontroller 1630, an SPI/SDIO controller 1635, and an I²S/I²C controller1640. In at least one embodiment, integrated circuit 1600 can include adisplay device 1645 coupled to one or more of a high-definitionmultimedia interface (“HDMI”) controller 1650 and a mobile industryprocessor interface (“MIPI”) display interface 1655. In at least oneembodiment, storage may be provided by a flash memory subsystem 1660including flash memory and a flash memory controller. In at least oneembodiment, a memory interface may be provided via a memory controller1665 for access to SDRAM or SRAM memory devices. In at least oneembodiment, some integrated circuits additionally include an embeddedsecurity engine 1670.

FIG. 17 illustrates a computing system 1700, according to at least oneembodiment; In at least one embodiment, computing system 1700 includes aprocessing subsystem 1701 having one or more processor(s) 1702 and asystem memory 1704 communicating via an interconnection path that mayinclude a memory hub 1705. In at least one embodiment, memory hub 1705may be a separate component within a chipset component or may beintegrated within one or more processor(s) 1702. In at least oneembodiment, memory hub 1705 couples with an I/O subsystem 1711 via acommunication link 1706. In at least one embodiment, I/O subsystem 1711includes an I/O hub 1707 that can enable computing system 1700 toreceive input from one or more input device(s) 1708. In at least oneembodiment, I/O hub 1707 can enable a display controller, which may beincluded in one or more processor(s) 1702, to provide outputs to one ormore display device(s) 1710A. In at least one embodiment, one or moredisplay device(s) 1710A coupled with I/O hub 1707 can include a local,internal, or embedded display device.

In at least one embodiment, processing subsystem 1701 includes one ormore parallel processor(s) 1712 coupled to memory hub 1705 via a bus orother communication link 1713. In at least one embodiment, communicationlink 1713 may be one of any number of standards based communication linktechnologies or protocols, such as, but not limited to PCIe, or may be avendor specific communications interface or communications fabric. In atleast one embodiment, one or more parallel processor(s) 1712 form acomputationally focused parallel or vector processing system that caninclude a large number of processing cores and/or processing clusters,such as a many integrated core processor. In at least one embodiment,one or more parallel processor(s) 1712 form a graphics processingsubsystem that can output pixels to one of one or more display device(s)1710A coupled via I/O Hub 1707. In at least one embodiment, one or moreparallel processor(s) 1712 can also include a display controller anddisplay interface (not shown) to enable a direct connection to one ormore display device(s) 1710B.

In at least one embodiment, a system storage unit 1714 can connect toI/O hub 1707 to provide a storage mechanism for computing system 1700.In at least one embodiment, an I/O switch 1716 can be used to provide aninterface mechanism to enable connections between I/O hub 1707 and othercomponents, such as a network adapter 1718 and/or wireless networkadapter 1719 that may be integrated into a platform, and various otherdevices that can be added via one or more add-in device(s) 1720. In atleast one embodiment, network adapter 1718 can be an Ethernet adapter oranother wired network adapter. In at least one embodiment, wirelessnetwork adapter 1719 can include one or more of a Wi-Fi, Bluetooth, NFC,or other network device that includes one or more wireless radios.

In at least one embodiment, computing system 1700 can include othercomponents not explicitly shown, including USB or other portconnections, optical storage drives, video capture devices, and thelike, that may also be connected to I/O hub 1707. In at least oneembodiment, communication paths interconnecting various components inFIG. 17 may be implemented using any suitable protocols, such as PCIbased protocols (e.g., PCIe), or other bus or point-to-pointcommunication interfaces and/or protocol(s), such as NVLink high-speedinterconnect, or interconnect protocols.

In at least one embodiment, one or more parallel processor(s) 1712incorporate circuitry optimized for graphics and video processing,including, for example, video output circuitry, and constitutes agraphics processing unit (“GPU”). In at least one embodiment, one ormore parallel processor(s) 1712 incorporate circuitry optimized forgeneral purpose processing. In at least embodiment, components ofcomputing system 1700 may be integrated with one or more other systemelements on a single integrated circuit. For example, in at least oneembodiment, one or more parallel processor(s) 1712, memory hub 1705,processor(s) 1702, and I/O hub 1707 can be integrated into an SoCintegrated circuit. In at least one embodiment, components of computingsystem 1700 can be integrated into a single package to form a system inpackage (“SIP”) configuration. In at least one embodiment, at least aportion of the components of computing system 1700 can be integratedinto a multi-chip module (“MCM”), which can be interconnected with othermulti-chip modules into a modular computing system. In at least oneembodiment, I/O subsystem 1711 and display devices 1710B are omittedfrom computing system 1700.

Processing Systems

The following FIGS. set forth, without limitation, exemplary processingsystems that can be used to implement at least one embodiment.

FIG. 18 illustrates an accelerated processing unit (“APU”) 1800, inaccordance with at least one embodiment. In at least one embodiment, APU1800 is developed by AMD Corporation of Santa Clara, Calif. In at leastone embodiment, APU 1800 can be configured to execute an applicationprogram, such as a CUDA program. In at least one embodiment, APU 1800includes, without limitation, a core complex 1810, a graphics complex1840, fabric 1860, I/O interfaces 1870, memory controllers 1880, adisplay controller 1892, and a multimedia engine 1894. In at least oneembodiment, APU 1800 may include, without limitation, any number of corecomplexes 1810, any number of graphics complexes 1850, any number ofdisplay controllers 1892, and any number of multimedia engines 1894 inany combination. For explanatory purposes, multiple instances of likeobjects are denoted herein with reference numbers identifying the objectand parenthetical numbers identifying the instance where needed.

In at least one embodiment, core complex 1810 is a CPU, graphics complex1840 is a GPU, and APU 1800 is a processing unit that integrates,without limitation, 1810 and 1840 onto a single chip. In at least oneembodiment, some tasks may be assigned to core complex 1810 and othertasks may be assigned to graphics complex 1840. In at least oneembodiment, core complex 1810 is configured to execute main controlsoftware associated with APU 1800, such as an operating system. In atleast one embodiment, core complex 1810 is the master processor of APU1800, controlling and coordinating operations of other processors. In atleast one embodiment, core complex 1810 issues commands that control theoperation of graphics complex 1840. In at least one embodiment, corecomplex 1810 can be configured to execute host executable code derivedfrom CUDA source code, and graphics complex 1840 can be configured toexecute device executable code derived from CUDA source code.

In at least one embodiment, core complex 1810 includes, withoutlimitation, cores 1820(1)-1820(4) and an L3 cache 1830. In at least oneembodiment, core complex 1810 may include, without limitation, anynumber of cores 1820 and any number and type of caches in anycombination. In at least one embodiment, cores 1820 are configured toexecute instructions of a particular instruction set architecture(“ISA”). In at least one embodiment, each core 1820 is a CPU core.

In at least one embodiment, each core 1820 includes, without limitation,a fetch/decode unit 1822, an integer execution engine 1824, a floatingpoint execution engine 1826, and an L2 cache 1828. In at least oneembodiment, fetch/decode unit 1822 fetches instructions, decodes suchinstructions, generates micro-operations, and dispatches separatemicro-instructions to integer execution engine 1824 and floating pointexecution engine 1826. In at least one embodiment, fetch/decode unit1822 can concurrently dispatch one micro-instruction to integerexecution engine 1824 and another micro-instruction to floating pointexecution engine 1826. In at least one embodiment, integer executionengine 1824 executes, without limitation, integer and memory operations.In at least one embodiment, floating point engine 1826 executes, withoutlimitation, floating point and vector operations. In at least oneembodiment, fetch-decode unit 1822 dispatches micro-instructions to asingle execution engine that replaces both integer execution engine 1824and floating point execution engine 1826.

In at least one embodiment, each core 1820(i), where i is an integerrepresenting a particular instance of core 1820, may access L2 cache1828(i) included in core 1820(i). In at least one embodiment, each core1820 included in core complex 1810(j), where j is an integerrepresenting a particular instance of core complex 1810, is connected toother cores 1820 included in core complex 1810(j) via L3 cache 1830(j)included in core complex 1810(j). In at least one embodiment, cores 1820included in core complex 1810(j), where j is an integer representing aparticular instance of core complex 1810, can access all of L3 cache1830(j) included in core complex 1810(j). In at least one embodiment, L3cache 1830 may include, without limitation, any number of slices.

In at least one embodiment, graphics complex 1840 can be configured toperform compute operations in a highly-parallel fashion. In at least oneembodiment, graphics complex 1840 is configured to execute graphicspipeline operations such as draw commands, pixel operations, geometriccomputations, and other operations associated with rendering an image toa display. In at least one embodiment, graphics complex 1840 isconfigured to execute operations unrelated to graphics. In at least oneembodiment, graphics complex 1840 is configured to execute bothoperations related to graphics and operations unrelated to graphics.

In at least one embodiment, graphics complex 1840 includes, withoutlimitation, any number of compute units 1850 and an L2 cache 1842. In atleast one embodiment, compute units 1850 share L2 cache 1842. In atleast one embodiment, L2 cache 1842 is partitioned. In at least oneembodiment, graphics complex 1840 includes, without limitation, anynumber of compute units 1850 and any number (including zero) and type ofcaches. In at least one embodiment, graphics complex 1840 includes,without limitation, any amount of dedicated graphics hardware.

In at least one embodiment, each compute unit 1850 includes, withoutlimitation, any number of SIMD units 1852 and a shared memory 1854. Inat least one embodiment, each SIMD unit 1852 implements a SIMDarchitecture and is configured to perform operations in parallel. In atleast one embodiment, each compute unit 1850 may execute any number ofthread blocks, but each thread block executes on a single compute unit1850. In at least one embodiment, a thread block includes, withoutlimitation, any number of threads of execution. In at least oneembodiment, a workgroup is a thread block. In at least one embodiment,each SIMD unit 1852 executes a different warp. In at least oneembodiment, a warp is a group of threads (e.g., 16 threads), where eachthread in the warp belongs to a single thread block and is configured toprocess a different set of data based on a single set of instructions.In at least one embodiment, predication can be used to disable one ormore threads in a warp. In at least one embodiment, a lane is a thread.In at least one embodiment, a work item is a thread. In at least oneembodiment, a wavefront is a warp. In at least one embodiment, differentwavefronts in a thread block may synchronize together and communicatevia shared memory 1854.

In at least one embodiment, fabric 1860 is a system interconnect thatfacilitates data and control transmissions across core complex 1810,graphics complex 1840, I/O interfaces 1870, memory controllers 1880,display controller 1892, and multimedia engine 1894. In at least oneembodiment, APU 1800 may include, without limitation, any amount andtype of system interconnect in addition to or instead of fabric 1860that facilitates data and control transmissions across any number andtype of directly or indirectly linked components that may be internal orexternal to APU 1800. In at least one embodiment, I/O interfaces 1870are representative of any number and type of I/O interfaces (e.g., PCI,PCI-Extended (“PCI-X”), PCIe, gigabit Ethernet (“GBE”), USB, etc.). Inat least one embodiment, various types of peripheral devices are coupledto I/O interfaces 1870 In at least one embodiment, peripheral devicesthat are coupled to I/O interfaces 1870 may include, without limitation,keyboards, mice, printers, scanners, joysticks or other types of gamecontrollers, media recording devices, external storage devices, networkinterface cards, and so forth.

In at least one embodiment, display controller AMD92 displays images onone or more display device(s), such as a liquid crystal display (“LCD”)device. In at least one embodiment, multimedia engine 240 includes,without limitation, any amount and type of circuitry that is related tomultimedia, such as a video decoder, a video encoder, an image signalprocessor, etc. In at least one embodiment, memory controllers 1880facilitate data transfers between APU 1800 and a unified system memory1890. In at least one embodiment, core complex 1810 and graphics complex1840 share unified system memory 1890.

In at least one embodiment, APU 1800 implements a memory subsystem thatincludes, without limitation, any amount and type of memory controllers1880 and memory devices (e.g., shared memory 1854) that may be dedicatedto one component or shared among multiple components. In at least oneembodiment, APU 1800 implements a cache subsystem that includes, withoutlimitation, one or more cache memories (e.g., L2 caches 1928, L3 cache1830, and L2 cache 1842) that may each be private to or shared betweenany number of components (e.g., cores 1820, core complex 1810, SIMDunits 1852, compute units 1850, and graphics complex 1840).

FIG. 19 illustrates a CPU 1900, in accordance with at least oneembodiment. In at least one embodiment, CPU 1900 is developed by AMDCorporation of Santa Clara, Calif. In at least one embodiment, CPU 1900can be configured to execute an application program. In at least oneembodiment, CPU 1900 is configured to execute main control software,such as an operating system. In at least one embodiment, CPU 1900 issuescommands that control the operation of an external GPU (not shown). Inat least one embodiment, CPU 1900 can be configured to execute hostexecutable code derived from CUDA source code, and an external GPU canbe configured to execute device executable code derived from such CUDAsource code. In at least one embodiment, CPU 1900 includes, withoutlimitation, any number of core complexes 1910, fabric 1960, I/Ointerfaces 1970, and memory controllers 1980.

In at least one embodiment, core complex 1910 includes, withoutlimitation, cores 1920(1)-1920(4) and an L3 cache 1930. In at least oneembodiment, core complex 1910 may include, without limitation, anynumber of cores 1920 and any number and type of caches in anycombination. In at least one embodiment, cores 1920 are configured toexecute instructions of a particular ISA. In at least one embodiment,each core 1920 is a CPU core.

In at least one embodiment, each core 1920 includes, without limitation,a fetch/decode unit 1922, an integer execution engine 1924, a floatingpoint execution engine 1926, and an L2 cache 1928. In at least oneembodiment, fetch/decode unit 1922 fetches instructions, decodes suchinstructions, generates micro-operations, and dispatches separatemicro-instructions to integer execution engine 1924 and floating pointexecution engine 1926. In at least one embodiment, fetch/decode unit1922 can concurrently dispatch one micro-instruction to integerexecution engine 1924 and another micro-instruction to floating pointexecution engine 1926. In at least one embodiment, integer executionengine 1924 executes, without limitation, integer and memory operations.In at least one embodiment, floating point engine 1926 executes, withoutlimitation, floating point and vector operations. In at least oneembodiment, fetch-decode unit 1922 dispatches micro-instructions to asingle execution engine that replaces both integer execution engine 1924and floating point execution engine 1926.

In at least one embodiment, each core 1920(i), where i is an integerrepresenting a particular instance of core 1920, may access L2 cache1928(i) included in core 1920(i). In at least one embodiment, each core1920 included in core complex 1910(j), where j is an integerrepresenting a particular instance of core complex 1910, is connected toother cores 1920 in core complex 1910(j) via L3 cache 1930(j) includedin core complex 1910(j). In at least one embodiment, cores 1920 includedin core complex 1910(j), where j is an integer representing a particularinstance of core complex 1910, can access all of L3 cache 1930(j)included in core complex 1910(j). In at least one embodiment, L3 cache1930 may include, without limitation, any number of slices.

In at least one embodiment, fabric 1960 is a system interconnect thatfacilitates data and control transmissions across core complexes1910(1)-1910(N) (where N is an integer greater than zero), I/Ointerfaces 1970, and memory controllers 1980. In at least oneembodiment, CPU 1900 may include, without limitation, any amount andtype of system interconnect in addition to or instead of fabric 1960that facilitates data and control transmissions across any number andtype of directly or indirectly linked components that may be internal orexternal to CPU 1900. In at least one embodiment, I/O interfaces 1970are representative of any number and type of I/O interfaces (e.g., PCI,PCI-X, PCIe, GBE, USB, etc.). In at least one embodiment, various typesof peripheral devices are coupled to I/O interfaces 1970 In at least oneembodiment, peripheral devices that are coupled to I/O interfaces 1970may include, without limitation, displays, keyboards, mice, printers,scanners, joysticks or other types of game controllers, media recordingdevices, external storage devices, network interface cards, and soforth.

In at least one embodiment, memory controllers 1980 facilitate datatransfers between CPU 1900 and a system memory 1990. In at least oneembodiment, core complex 1910 and graphics complex 1940 share systemmemory 1990. In at least one embodiment, CPU 1900 implements a memorysubsystem that includes, without limitation, any amount and type ofmemory controllers 1980 and memory devices that may be dedicated to onecomponent or shared among multiple components. In at least oneembodiment, CPU 1900 implements a cache subsystem that includes, withoutlimitation, one or more cache memories (e.g., L2 caches 1928 and L3caches 1930) that may each be private to or shared between any number ofcomponents (e.g., cores 1920 and core complexes 1910).

FIG. 20 illustrates an exemplary accelerator integration slice 2090, inaccordance with at least one embodiment. As used herein, a “slice”comprises a specified portion of processing resources of an acceleratorintegration circuit. In at least one embodiment, the acceleratorintegration circuit provides cache management, memory access, contextmanagement, and interrupt management services on behalf of multiplegraphics processing engines included in a graphics acceleration module.The graphics processing engines may each comprise a separate GPU.Alternatively, the graphics processing engines may comprise differenttypes of graphics processing engines within a GPU such as graphicsexecution units, media processing engines (e.g., videoencoders/decoders), samplers, and blit engines. In at least oneembodiment, the graphics acceleration module may be a GPU with multiplegraphics processing engines. In at least one embodiment, the graphicsprocessing engines may be individual GPUs integrated on a commonpackage, line card, or chip.

An application effective address space 2082 within system memory 2014stores process elements 2083. In one embodiment, process elements 2083are stored in response to GPU invocations 2081 from applications 2080executed on processor 2007. A process element 2083 contains processstate for corresponding application 2080. A work descriptor (“WD”) 2084contained in process element 2083 can be a single job requested by anapplication or may contain a pointer to a queue of jobs. In at least oneembodiment, WD 2084 is a pointer to a job request queue in applicationeffective address space 2082.

Graphics acceleration module 2046 and/or individual graphics processingengines can be shared by all or a subset of processes in a system. In atleast one embodiment, an infrastructure for setting up process state andsending WD 2084 to graphics acceleration module 2046 to start a job in avirtualized environment may be included.

In at least one embodiment, a dedicated-process programming model isimplementation-specific. In this model, a single process owns graphicsacceleration module 2046 or an individual graphics processing engine.Because graphics acceleration module 2046 is owned by a single process,a hypervisor initializes an accelerator integration circuit for anowning partition and an operating system initializes acceleratorintegration circuit for an owning process when graphics accelerationmodule 2046 is assigned.

In operation, a WD fetch unit 2091 in accelerator integration slice 2090fetches next WD 2084 which includes an indication of work to be done byone or more graphics processing engines of graphics acceleration module2046. Data from WD 2084 may be stored in registers 2045 and used by amemory management unit (“MMU”) 2039, interrupt management circuit 2047and/or context management circuit 2048 as illustrated. For example, oneembodiment of MMU 2039 includes segment/page walk circuitry foraccessing segment/page tables 2086 within OS virtual address space 2085.Interrupt management circuit 2047 may process interrupt events (“INT”)2092 received from graphics acceleration module 2046. When performinggraphics operations, an effective address 2093 generated by a graphicsprocessing engine is translated to a real address by MMU 2039.

In one embodiment, a same set of registers 2045 are duplicated for eachgraphics processing engine and/or graphics acceleration module 2046 andmay be initialized by a hypervisor or operating system. Each of theseduplicated registers may be included in accelerator integration slice2090. Exemplary registers that may be initialized by a hypervisor areshown in Table 1.

TABLE 1 Hypervisor Initialized Registers 1 Slice Control Register 2 RealAddress (RA) Scheduled Processes Area Pointer 3 Authority Mask OverrideRegister 4 Interrupt Vector Table Entry Offset 5 Interrupt Vector TableEntry Limit 6 State Register 7 Logical Partition ID 8 Real address (RA)Hypervisor Accelerator Utilization Record Pointer 9 Storage DescriptionRegister

Exemplary registers that may be initialized by an operating system areshown in Table 2.

TABLE 2 Operating System Initialized Registers 1 Process and ThreadIdentification 2 Effective Address (EA) Context Save/Restore Pointer 3Virtual Address (VA) Accelerator Utilization Record Pointer 4 VirtualAddress (VA) Storage Segment Table Pointer 5 Authority Mask 6 Workdescriptor

In one embodiment, each WD 2084 is specific to a particular graphicsacceleration module 2046 and/or a particular graphics processing engine.It contains all information required by a graphics processing engine todo work or it can be a pointer to a memory location where an applicationhas set up a command queue of work to be completed.

FIGS. 21A and 21B illustrate exemplary graphics processors, inaccordance with at least one embodiment. In at least one embodiment, anyof the exemplary graphics processors may be fabricated using one or moreIP cores. In addition to what is illustrated, other logic and circuitsmay be included in at least one embodiment, including additionalgraphics processors/cores, peripheral interface controllers, orgeneral-purpose processor cores. In at least one embodiment, theexemplary graphics processors are for use within an SoC.

FIG. 21A illustrates an exemplary graphics processor 2110 of an SoCintegrated circuit that may be fabricated using one or more IP cores, inaccordance with at least one embodiment. FIG. 21B illustrates anadditional exemplary graphics processor 2140 of an SoC integratedcircuit that may be fabricated using one or more IP cores, in accordancewith at least one embodiment. In at least one embodiment, graphicsprocessor 2110 of FIG. 21A is a low power graphics processor core. In atleast one embodiment, graphics processor 2140 of FIG. 21B is a higherperformance graphics processor core. In at least one embodiment, each ofgraphics processors 2110, 2140 can be variants of graphics processor1610 of FIG. 16 .

In at least one embodiment, graphics processor 2110 includes a vertexprocessor 2105 and one or more fragment processor(s) 2115A-2115N (e.g.,2115A, 2115B, 2115C, 2115D, through 2115N-1, and 2115N). In at least oneembodiment, graphics processor 2110 can execute different shaderprograms via separate logic, such that vertex processor 2105 isoptimized to execute operations for vertex shader programs, while one ormore fragment processor(s) 2115A-2115N execute fragment (e.g., pixel)shading operations for fragment or pixel shader programs. In at leastone embodiment, vertex processor 2105 performs a vertex processing stageof a 3D graphics pipeline and generates primitives and vertex data. Inat least one embodiment, fragment processor(s) 2115A-2115N use primitiveand vertex data generated by vertex processor 2105 to produce aframebuffer that is displayed on a display device. In at least oneembodiment, fragment processor(s) 2115A-2115N are optimized to executefragment shader programs as provided for in an OpenGL API, which may beused to perform similar operations as a pixel shader program as providedfor in a Direct 3D API.

In at least one embodiment, graphics processor 2110 additionallyincludes one or more MMU(s) 2120A-2120B, cache(s) 2125A-2125B, andcircuit interconnect(s) 2130A-2130B. In at least one embodiment, one ormore MMU(s) 2120A-2120B provide for virtual to physical address mappingfor graphics processor 2110, including for vertex processor 2105 and/orfragment processor(s) 2115A-2115N, which may reference vertex orimage/texture data stored in memory, in addition to vertex orimage/texture data stored in one or more cache(s) 2125A-2125B. In atleast one embodiment, one or more MMU(s) 2120A-2120B may be synchronizedwith other MMUs within a system, including one or more MMUs associatedwith one or more application processor(s) 1605, image processors 1615,and/or video processors 1620 of FIG. 16 , such that each processor1605-1620 can participate in a shared or unified virtual memory system.In at least one embodiment, one or more circuit interconnect(s)2130A-2130B enable graphics processor 2110 to interface with other IPcores within an SoC, either via an internal bus of the SoC or via adirect connection.

In at least one embodiment, graphics processor 2140 includes one or moreMMU(s) 2120A-2120B, caches 2125A-2125B, and circuit interconnects2130A-2130B of graphics processor 2110 of FIG. 21A. In at least oneembodiment, graphics processor 2140 includes one or more shader core(s)2155A-2155N (e.g., 2155A, 2155B, 2155C, 2155D, 2155E, 2155F, through2155N-1, and 2155N), which provides for a unified shader corearchitecture in which a single core or type or core can execute alltypes of programmable shader code, including shader program code toimplement vertex shaders, fragment shaders, and/or compute shaders. Inat least one embodiment, a number of shader cores can vary. In at leastone embodiment, graphics processor 2140 includes an inter-core taskmanager 2145, which acts as a thread dispatcher to dispatch executionthreads to one or more shader cores 2155A-2155N and a tiling unit 2158to accelerate tiling operations for tile-based rendering, in whichrendering operations for a scene are subdivided in image space, forexample to exploit local spatial coherence within a scene or to optimizeuse of internal caches.

FIG. 22A illustrates a graphics core 2200, in accordance with at leastone embodiment. In at least one embodiment, graphics core 2200 may beincluded within graphics processor 1610 of FIG. 16 . In at least oneembodiment, graphics core 2200 may be a unified shader core 2155A-2155Nas in FIG. 21B. In at least one embodiment, graphics core 2200 includesa shared instruction cache 2202, a texture unit 2218, and a cache/sharedmemory 2220 that are common to execution resources within graphics core2200. In at least one embodiment, graphics core 2200 can includemultiple slices 2201A-2201N or partition for each core, and a graphicsprocessor can include multiple instances of graphics core 2200. Slices2201A-2201N can include support logic including a local instructioncache 2204A-2204N, a thread scheduler 2206A-2206N, a thread dispatcher2208A-2208N, and a set of registers 2210A-2210N. In at least oneembodiment, slices 2201A-2201N can include a set of additional functionunits (“AFUs”) 2212A-2212N, floating-point units (“FPUs”) 2214A-2214N,integer arithmetic logic units (“ALUs”) 2216-2216N, addresscomputational units (“ACUs”) 2213A-2213N, double-precisionfloating-point units (“DPFPUs”) 2215A-2215N, and matrix processing units(“MPUs”) 2217A-2217N.

In at least one embodiment, FPUs 2214A-2214N can performsingle-precision (32-bit) and half-precision (16-bit) floating pointoperations, while DPFPUs 2215A-2215N perform double precision (64-bit)floating point operations. In at least one embodiment, ALUs 2216A-2216Ncan perform variable precision integer operations at 8-bit, 16-bit, and32-bit precision, and can be configured for mixed precision operations.In at least one embodiment, MPUs 2217A-2217N can also be configured formixed precision matrix operations, including half-precision floatingpoint and 8-bit integer operations. In at least one embodiment, MPUs2217-2217N can perform a variety of matrix operations to accelerate CUDAprograms, including enabling support for accelerated general matrix tomatrix multiplication (“GEMM”). In at least one embodiment, AFUs2212A-2212N can perform additional logic operations not supported byfloating-point or integer units, including trigonometric operations(e.g., Sine, Cosine, etc.).

FIG. 22B illustrates a general-purpose graphics processing unit(“GPGPU”) 2230, in accordance with at least one embodiment. In at leastone embodiment, GPGPU 2230 is highly-parallel and suitable fordeployment on a multi-chip module. In at least one embodiment, GPGPU2230 can be configured to enable highly-parallel compute operations tobe performed by an array of GPUs. In at least one embodiment, GPGPU 2230can be linked directly to other instances of GPGPU 2230 to create amulti-GPU cluster to improve execution time for CUDA programs. In atleast one embodiment, GPGPU 2230 includes a host interface 2232 toenable a connection with a host processor. In at least one embodiment,host interface 2232 is a PCIe interface. In at least one embodiment,host interface 2232 can be a vendor specific communications interface orcommunications fabric. In at least one embodiment, GPGPU 2230 receivescommands from a host processor and uses a global scheduler 2234 todistribute execution threads associated with those commands to a set ofcompute clusters 2236A-2236H. In at least one embodiment, computeclusters 2236A-2236H share a cache memory 2238. In at least oneembodiment, cache memory 2238 can serve as a higher-level cache forcache memories within compute clusters 2236A-2236H.

In at least one embodiment, GPGPU 2230 includes memory 2244A-2244Bcoupled with compute clusters 2236A-2236H via a set of memorycontrollers 2242A-2242B. In at least one embodiment, memory 2244A-2244Bcan include various types of memory devices including DRAM or graphicsrandom access memory, such as synchronous graphics random access memory(“SGRAM”), including graphics double data rate (“GDDR”) memory.

In at least one embodiment, compute clusters 2236A-2236H each include aset of graphics cores, such as graphics core 2200 of FIG. 22A, which caninclude multiple types of integer and floating point logic units thatcan perform computational operations at a range of precisions includingsuited for computations associated with CUDA programs. For example, inat least one embodiment, at least a subset of floating point units ineach of compute clusters 2236A-2236H can be configured to perform 16-bitor 32-bit floating point operations, while a different subset offloating point units can be configured to perform 64-bit floating pointoperations.

In at least one embodiment, multiple instances of GPGPU 2230 can beconfigured to operate as a compute cluster. Compute clusters 2236A-2236Hmay implement any technically feasible communication techniques forsynchronization and data exchange. In at least one embodiment, multipleinstances of GPGPU 2230 communicate over host interface 2232. In atleast one embodiment, GPGPU 2230 includes an I/O hub 2239 that couplesGPGPU 2230 with a GPU link 2240 that enables a direct connection toother instances of GPGPU 2230. In at least one embodiment, GPU link 2240is coupled to a dedicated GPU-to-GPU bridge that enables communicationand synchronization between multiple instances of GPGPU 2230. In atleast one embodiment GPU link 2240 couples with a high speedinterconnect to transmit and receive data to other GPGPUs 2230 orparallel processors. In at least one embodiment, multiple instances ofGPGPU 2230 are located in separate data processing systems andcommunicate via a network device that is accessible via host interface2232. In at least one embodiment GPU link 2240 can be configured toenable a connection to a host processor in addition to or as analternative to host interface 2232. In at least one embodiment, GPGPU2230 can be configured to execute a CUDA program.

FIG. 23A illustrates a parallel processor 2300, in accordance with atleast one embodiment. In at least one embodiment, various components ofparallel processor 2300 may be implemented using one or more integratedcircuit devices, such as programmable processors, application specificintegrated circuits (“ASICs”), or FPGAs.

In at least one embodiment, parallel processor 2300 includes a parallelprocessing unit 2302. In at least one embodiment, parallel processingunit 2302 includes an I/O unit 2304 that enables communication withother devices, including other instances of parallel processing unit2302. In at least one embodiment, I/O unit 2304 may be directlyconnected to other devices. In at least one embodiment, I/O unit 2304connects with other devices via use of a hub or switch interface, suchas memory hub 2305. In at least one embodiment, connections betweenmemory hub 2305 and I/O unit 2304 form a communication link. In at leastone embodiment, I/O unit 2304 connects with a host interface 2306 and amemory crossbar 2316, where host interface 2306 receives commandsdirected to performing processing operations and memory crossbar 2316receives commands directed to performing memory operations.

In at least one embodiment, when host interface 2306 receives a commandbuffer via I/O unit 2304, host interface 2306 can direct work operationsto perform those commands to a front end 2308. In at least oneembodiment, front end 2308 couples with a scheduler 2310, which isconfigured to distribute commands or other work items to a processingarray 2312. In at least one embodiment, scheduler 2310 ensures thatprocessing array 2312 is properly configured and in a valid state beforetasks are distributed to processing array 2312. In at least oneembodiment, scheduler 2310 is implemented via firmware logic executingon a microcontroller. In at least one embodiment, microcontrollerimplemented scheduler 2310 is configurable to perform complex schedulingand work distribution operations at coarse and fine granularity,enabling rapid preemption and context switching of threads executing onprocessing array 2312. In at least one embodiment, host software canprove workloads for scheduling on processing array 2312 via one ofmultiple graphics processing doorbells. In at least one embodiment,workloads can then be automatically distributed across processing array2312 by scheduler 2310 logic within a microcontroller includingscheduler 2310.

In at least one embodiment, processing array 2312 can include up to “N”clusters (e.g., cluster 2314A, cluster 2314B, through cluster 2314N). Inat least one embodiment, each cluster 2314A-2314N of processing array2312 can execute a large number of concurrent threads. In at least oneembodiment, scheduler 2310 can allocate work to clusters 2314A-2314N ofprocessing array 2312 using various scheduling and/or work distributionalgorithms, which may vary depending on the workload arising for eachtype of program or computation. In at least one embodiment, schedulingcan be handled dynamically by scheduler 2310, or can be assisted in partby compiler logic during compilation of program logic configured forexecution by processing array 2312. In at least one embodiment,different clusters 2314A-2314N of processing array 2312 can be allocatedfor processing different types of programs or for performing differenttypes of computations.

In at least one embodiment, processing array 2312 can be configured toperform various types of parallel processing operations. In at least oneembodiment, processing array 2312 is configured to performgeneral-purpose parallel compute operations. For example, in at leastone embodiment, processing array 2312 can include logic to executeprocessing tasks including filtering of video and/or audio data,performing modeling operations, including physics operations, andperforming data transformations.

In at least one embodiment, processing array 2312 is configured toperform parallel graphics processing operations. In at least oneembodiment, processing array 2312 can include additional logic tosupport execution of such graphics processing operations, including, butnot limited to texture sampling logic to perform texture operations, aswell as tessellation logic and other vertex processing logic. In atleast one embodiment, processing array 2312 can be configured to executegraphics processing related shader programs such as, but not limited tovertex shaders, tessellation shaders, geometry shaders, and pixelshaders. In at least one embodiment, parallel processing unit 2302 cantransfer data from system memory via I/O unit 2304 for processing. In atleast one embodiment, during processing, transferred data can be storedto on-chip memory (e.g., a parallel processor memory 2322) duringprocessing, then written back to system memory.

In at least one embodiment, when parallel processing unit 2302 is usedto perform graphics processing, scheduler 2310 can be configured todivide a processing workload into approximately equal sized tasks, tobetter enable distribution of graphics processing operations to multipleclusters 2314A-2314N of processing array 2312. In at least oneembodiment, portions of processing array 2312 can be configured toperform different types of processing. For example, in at least oneembodiment, a first portion may be configured to perform vertex shadingand topology generation, a second portion may be configured to performtessellation and geometry shading, and a third portion may be configuredto perform pixel shading or other screen space operations, to produce arendered image for display. In at least one embodiment, intermediatedata produced by one or more of clusters 2314A-2314N may be stored inbuffers to allow intermediate data to be transmitted between clusters2314A-2314N for further processing.

In at least one embodiment, processing array 2312 can receive processingtasks to be executed via scheduler 2310, which receives commandsdefining processing tasks from front end 2308. In at least oneembodiment, processing tasks can include indices of data to beprocessed, e.g., surface (patch) data, primitive data, vertex data,and/or pixel data, as well as state parameters and commands defining howdata is to be processed (e.g., what program is to be executed). In atleast one embodiment, scheduler 2310 may be configured to fetch indicescorresponding to tasks or may receive indices from front end 2308. In atleast one embodiment, front end 2308 can be configured to ensureprocessing array 2312 is configured to a valid state before a workloadspecified by incoming command buffers batch-buffers, push buffers, etc.)is initiated.

In at least one embodiment, each of one or more instances of parallelprocessing unit 2302 can couple with parallel processor memory 2322. Inat least one embodiment, parallel processor memory 2322 can be accessedvia memory crossbar 2316, which can receive memory requests fromprocessing array 2312 as well as I/O unit 2304. In at least oneembodiment, memory crossbar 2316 can access parallel processor memory2322 via a memory interface 2318. In at least one embodiment, memoryinterface 2318 can include multiple partition units (e.g., a partitionunit 2320A, partition unit 2320B, through partition unit 2320N) that caneach couple to a portion (e.g., memory unit) of parallel processormemory 2322. In at least one embodiment, a number of partition units2320A-2320N is configured to be equal to a number of memory units, suchthat a first partition unit 2320A has a corresponding first memory unit2324A, a second partition unit 2320B has a corresponding memory unit2324B, and an Nth partition unit 2320N has a corresponding Nth memoryunit 2324N. In at least one embodiment, a number of partition units2320A-2320N may not be equal to a number of memory devices.

In at least one embodiment, memory units 2324A-2324N can include varioustypes of memory devices, including DRAM or graphics random accessmemory, such as SGRAM, including GDDR memory. In at least oneembodiment, memory units 2324A-2324N may also include 3D stacked memory,including but not limited to high bandwidth memory (“HBM”). In at leastone embodiment, render targets, such as frame buffers or texture mapsmay be stored across memory units 2324A-2324N, allowing partition units2320A-2320N to write portions of each render target in parallel toefficiently use available bandwidth of parallel processor memory 2322.In at least one embodiment, a local instance of parallel processormemory 2322 may be excluded in favor of a unified memory design thatutilizes system memory in conjunction with local cache memory.

In at least one embodiment, any one of clusters 2314A-2314N ofprocessing array 2312 can process data that will be written to any ofmemory units 2324A-2324N within parallel processor memory 2322. In atleast one embodiment, memory crossbar 2316 can be configured to transferan output of each cluster 2314A-2314N to any partition unit 2320A-2320Nor to another cluster 2314A-2314N, which can perform additionalprocessing operations on an output. In at least one embodiment, eachcluster 2314A-2314N can communicate with memory interface 2318 throughmemory crossbar 2316 to read from or write to various external memorydevices. In at least one embodiment, memory crossbar 2316 has aconnection to memory interface 2318 to communicate with I/O unit 2304,as well as a connection to a local instance of parallel processor memory2322, enabling processing units within different clusters 2314A-2314N tocommunicate with system memory or other memory that is not local toparallel processing unit 2302. In at least one embodiment, memorycrossbar 2316 can use virtual channels to separate traffic streamsbetween clusters 2314A-2314N and partition units 2320A-2320N.

In at least one embodiment, multiple instances of parallel processingunit 2302 can be provided on a single add-in card, or multiple add-incards can be interconnected. In at least one embodiment, differentinstances of parallel processing unit 2302 can be configured tointeroperate even if different instances have different numbers ofprocessing cores, different amounts of local parallel processor memory,and/or other configuration differences. For example, in at least oneembodiment, some instances of parallel processing unit 2302 can includehigher precision floating point units relative to other instances. In atleast one embodiment, systems incorporating one or more instances ofparallel processing unit 2302 or parallel processor 2300 can beimplemented in a variety of configurations and form factors, includingbut not limited to desktop, laptop, or handheld personal computers,servers, workstations, game consoles, and/or embedded systems.

FIG. 23B illustrates a processing cluster 2394, in accordance with atleast one embodiment. In at least one embodiment, processing cluster2394 is included within a parallel processing unit. In at least oneembodiment, processing cluster 2394 is one of processing clusters2314A-2314N of FIG. 23 . In at least one embodiment, processing cluster2394 can be configured to execute many threads in parallel, where theterm “thread” refers to an instance of a particular program executing ona particular set of input data. In at least one embodiment, singleinstruction, multiple data (“SIMD”) instruction issue techniques areused to support parallel execution of a large number of threads withoutproviding multiple independent instruction units. In at least oneembodiment, single instruction, multiple thread (“SIMT”) techniques areused to support parallel execution of a large number of generallysynchronized threads, using a common instruction unit configured toissue instructions to a set of processing engines within each processingcluster 2394.

In at least one embodiment, operation of processing cluster 2394 can becontrolled via a pipeline manager 2332 that distributes processing tasksto SIMT parallel processors. In at least one embodiment, pipelinemanager 2332 receives instructions from scheduler 2310 of FIG. 23 andmanages execution of those instructions via a graphics multiprocessor2334 and/or a texture unit 2336. In at least one embodiment, graphicsmultiprocessor 2334 is an exemplary instance of a SIMT parallelprocessor. However, in at least one embodiment, various types of SIMTparallel processors of differing architectures may be included withinprocessing cluster 2394. In at least one embodiment, one or moreinstances of graphics multiprocessor 2334 can be included withinprocessing cluster 2394. In at least one embodiment, graphicsmultiprocessor 2334 can process data and a data crossbar 2340 can beused to distribute processed data to one of multiple possibledestinations, including other shader units. In at least one embodiment,pipeline manager 2332 can facilitate distribution of processed data byspecifying destinations for processed data to be distributed via datacrossbar 2340.

In at least one embodiment, each graphics multiprocessor 2334 withinprocessing cluster 2394 can include an identical set of functionalexecution logic (e.g., arithmetic logic units, load/store units(“LSUs”), etc.). In at least one embodiment, functional execution logiccan be configured in a pipelined manner in which new instructions can beissued before previous instructions are complete. In at least oneembodiment, functional execution logic supports a variety of operationsincluding integer and floating point arithmetic, comparison operations,Boolean operations, bit-shifting, and computation of various algebraicfunctions. In at least one embodiment, same functional-unit hardware canbe leveraged to perform different operations and any combination offunctional units may be present.

In at least one embodiment, instructions transmitted to processingcluster 2394 constitute a thread. In at least one embodiment, a set ofthreads executing across a set of parallel processing engines is athread group. In at least one embodiment, a thread group executes aprogram on different input data. In at least one embodiment, each threadwithin a thread group can be assigned to a different processing enginewithin graphics multiprocessor 2334. In at least one embodiment, athread group may include fewer threads than a number of processingengines within graphics multiprocessor 2334. In at least one embodiment,when a thread group includes fewer threads than a number of processingengines, one or more of the processing engines may be idle during cyclesin which that thread group is being processed. In at least oneembodiment, a thread group may also include more threads than a numberof processing engines within graphics multiprocessor 2334. In at leastone embodiment, when a thread group includes more threads than thenumber of processing engines within graphics multiprocessor 2334,processing can be performed over consecutive clock cycles. In at leastone embodiment, multiple thread groups can be executed concurrently ongraphics multiprocessor 2334.

In at least one embodiment, graphics multiprocessor 2334 includes aninternal cache memory to perform load and store operations. In at leastone embodiment, graphics multiprocessor 2334 can forego an internalcache and use a cache memory (e.g., L1 cache 2348) within processingcluster 2394. In at least one embodiment, each graphics multiprocessor2334 also has access to Level 2 (“L2”) caches within partition units(e.g., partition units 2320A-2320N of FIG. 23A) that are shared amongall processing clusters 2394 and may be used to transfer data betweenthreads. In at least one embodiment, graphics multiprocessor 2334 mayalso access off-chip global memory, which can include one or more oflocal parallel processor memory and/or system memory. In at least oneembodiment, any memory external to parallel processing unit 2302 may beused as global memory. In at least one embodiment, processing cluster2394 includes multiple instances of graphics multiprocessor 2334 thatcan share common instructions and data, which may be stored in L1 cache2348.

In at least one embodiment, each processing cluster 2394 may include anMMU 2345 that is configured to map virtual addresses into physicaladdresses. In at least one embodiment, one or more instances of MMU 2345may reside within memory interface 2318 of FIG. 23 . In at least oneembodiment, MMU 2345 includes a set of page table entries (“PTEs”) usedto map a virtual address to a physical address of a tile and optionallya cache line index. In at least one embodiment, MMU 2345 may includeaddress translation lookaside buffers (“TLBs”) or caches that may residewithin graphics multiprocessor 2334 or L1 cache 2348 or processingcluster 2394. In at least one embodiment, a physical address isprocessed to distribute surface data access locality to allow efficientrequest interleaving among partition units. In at least one embodiment,a cache line index may be used to determine whether a request for acache line is a hit or miss.

In at least one embodiment, processing cluster 2394 may be configuredsuch that each graphics multiprocessor 2334 is coupled to a texture unit2336 for performing texture mapping operations, e.g., determiningtexture sample positions, reading texture data, and filtering texturedata. In at least one embodiment, texture data is read from an internaltexture L1 cache (not shown) or from an L1 cache within graphicsmultiprocessor 2334 and is fetched from an L2 cache, local parallelprocessor memory, or system memory, as needed. In at least oneembodiment, each graphics multiprocessor 2334 outputs a processed taskto data crossbar 2340 to provide the processed task to anotherprocessing cluster 2394 for further processing or to store the processedtask in an L2 cache, a local parallel processor memory, or a systemmemory via memory crossbar 2316. In at least one embodiment, apre-raster operations unit (“preROP”) 2342 is configured to receive datafrom graphics multiprocessor 2334, direct data to ROP units, which maybe located with partition units as described herein (e.g., partitionunits 2320A-2320N of FIG. 23 ). In at least one embodiment, PreROP 2342can perform optimizations for color blending, organize pixel color data,and perform address translations.

FIG. 23C illustrates a graphics multiprocessor 2396, in accordance withat least one embodiment. In at least one embodiment, graphicsmultiprocessor 2396 is graphics multiprocessor 2334 of FIG. 23B. In atleast one embodiment, graphics multiprocessor 2396 couples with pipelinemanager 2332 of processing cluster 2394. In at least one embodiment,graphics multiprocessor 2396 has an execution pipeline including but notlimited to an instruction cache 2352, an instruction unit 2354, anaddress mapping unit 2356, a register file 2358, one or more GPGPU cores2362, and one or more LSUs 2366. GPGPU cores 2362 and LSUs 2366 arecoupled with cache memory 2372 and shared memory 2370 via a memory andcache interconnect 2368.

In at least one embodiment, instruction cache 2352 receives a stream ofinstructions to execute from pipeline manager 2332. In at least oneembodiment, instructions are cached in instruction cache 2352 anddispatched for execution by instruction unit 2354. In at least oneembodiment, instruction unit 2354 can dispatch instructions as threadgroups (e.g., warps), with each thread of a thread group assigned to adifferent execution unit within GPGPU core 2362. In at least oneembodiment, an instruction can access any of a local, shared, or globaladdress space by specifying an address within a unified address space.In at least one embodiment, address mapping unit 2356 can be used totranslate addresses in a unified address space into a distinct memoryaddress that can be accessed by LSUs 2366.

In at least one embodiment, register file 2358 provides a set ofregisters for functional units of graphics multiprocessor 2396. In atleast one embodiment, register file 2358 provides temporary storage foroperands connected to data paths of functional units (e.g., GPGPU cores2362, LSUs 2366) of graphics multiprocessor 2396. In at least oneembodiment, register file 2358 is divided between each of functionalunits such that each functional unit is allocated a dedicated portion ofregister file 2358. In at least one embodiment, register file 2358 isdivided between different thread groups being executed by graphicsmultiprocessor 2396.

In at least one embodiment, GPGPU cores 2362 can each include FPUsand/or integer ALUs that are used to execute instructions of graphicsmultiprocessor 2396. GPGPU cores 2362 can be similar in architecture orcan differ in architecture. In at least one embodiment, a first portionof GPGPU cores 2362 include a single precision FPU and an integer ALUwhile a second portion of GPGPU cores 2362 include a double precisionFPU. In at least one embodiment, FPUs can implement IEEE 754-2008standard for floating point arithmetic or enable variable precisionfloating point arithmetic. In at least one embodiment, graphicsmultiprocessor 2396 can additionally include one or more fixed functionor special function units to perform specific functions such as copyrectangle or pixel blending operations. In at least one embodiment oneor more of GPGPU cores 2362 can also include fixed or special functionlogic.

In at least one embodiment, GPGPU cores 2362 include SIMD logic capableof performing a single instruction on multiple sets of data. In at leastone embodiment GPGPU cores 2362 can physically execute SIMD4, SIMD8, andSIMD16 instructions and logically execute SIMD1, SIMD2, and SIMD32instructions. In at least one embodiment, SIMD instructions for GPGPUcores 2362 can be generated at compile time by a shader compiler orautomatically generated when executing programs written and compiled forsingle program multiple data (“SPMD”) or SIMT architectures. In at leastone embodiment, multiple threads of a program configured for an SIMTexecution model can executed via a single SIMD instruction. For example,in at least one embodiment, eight SIMT threads that perform the same orsimilar operations can be executed in parallel via a single SIMD8 logicunit.

In at least one embodiment, memory and cache interconnect 2368 is aninterconnect network that connects each functional unit of graphicsmultiprocessor 2396 to register file 2358 and to shared memory 2370. Inat least one embodiment, memory and cache interconnect 2368 is acrossbar interconnect that allows LSU 2366 to implement load and storeoperations between shared memory 2370 and register file 2358. In atleast one embodiment, register file 2358 can operate at a same frequencyas GPGPU cores 2362, thus data transfer between GPGPU cores 2362 andregister file 2358 is very low latency. In at least one embodiment,shared memory 2370 can be used to enable communication between threadsthat execute on functional units within graphics multiprocessor 2396. Inat least one embodiment, cache memory 2372 can be used as a data cachefor example, to cache texture data communicated between functional unitsand texture unit 2336. In at least one embodiment, shared memory 2370can also be used as a program managed cached. In at least oneembodiment, threads executing on GPGPU cores 2362 can programmaticallystore data within shared memory in addition to automatically cached datathat is stored within cache memory 2372.

In at least one embodiment, a parallel processor or GPGPU as describedherein is communicatively coupled to host/processor cores to accelerategraphics operations, machine-learning operations, pattern analysisoperations, and various general purpose GPU (GPGPU) functions. In atleast one embodiment, a GPU may be communicatively coupled to hostprocessor/cores over a bus or other interconnect (e.g., a high speedinterconnect such as PCIe or NVLink). In at least one embodiment, a GPUmay be integrated on the same package or chip as cores andcommunicatively coupled to cores over a processor bus/interconnect thatis internal to a package or a chip. In at least one embodiment,regardless of the manner in which a GPU is connected, processor coresmay allocate work to the GPU in the form of sequences ofcommands/instructions contained in a WD. In at least one embodiment, theGPU then uses dedicated circuitry/logic for efficiently processing thesecommands/instructions.

FIG. 24 illustrates a graphics processor 2400, in accordance with atleast one embodiment. In at least one embodiment, graphics processor2400 includes a ring interconnect 2402, a pipeline front-end 2404, amedia engine 2437, and graphics cores 2480A-2480N. In at least oneembodiment, ring interconnect 2402 couples graphics processor 2400 toother processing units, including other graphics processors or one ormore general-purpose processor cores. In at least one embodiment,graphics processor 2400 is one of many processors integrated within amulti-core processing system.

In at least one embodiment, graphics processor 2400 receives batches ofcommands via ring interconnect 2402. In at least one embodiment,incoming commands are interpreted by a command streamer 2403 in pipelinefront-end 2404. In at least one embodiment, graphics processor 2400includes scalable execution logic to perform 3D geometry processing andmedia processing via graphics core(s) 2480A-2480N. In at least oneembodiment, for 3D geometry processing commands, command streamer 2403supplies commands to geometry pipeline 2436. In at least one embodiment,for at least some media processing commands, command streamer 2403supplies commands to a video front end 2434, which couples with a mediaengine 2437. In at least one embodiment, media engine 2437 includes aVideo Quality Engine (“VQE”) 2430 for video and image post-processingand a multi-format encode/decode (“MFX”) engine 2433 to providehardware-accelerated media data encode and decode. In at least oneembodiment, geometry pipeline 2436 and media engine 2437 each generateexecution threads for thread execution resources provided by at leastone graphics core 2480A.

In at least one embodiment, graphics processor 2400 includes scalablethread execution resources featuring modular graphics cores 2480A-2480N(sometimes referred to as core slices), each having multiple sub-cores2450A-550N, 2460A-2460N (sometimes referred to as core sub-slices). Inat least one embodiment, graphics processor 2400 can have any number ofgraphics cores 2480A through 2480N. In at least one embodiment, graphicsprocessor 2400 includes a graphics core 2480A having at least a firstsub-core 2450A and a second sub-core 2460A. In at least one embodiment,graphics processor 2400 is a low power processor with a single sub-core(e.g., sub-core 2450A). In at least one embodiment, graphics processor2400 includes multiple graphics cores 2480A-2480N, each including a setof first sub-cores 2450A-2450N and a set of second sub-cores2460A-2460N. In at least one embodiment, each sub-core in firstsub-cores 2450A-2450N includes at least a first set of execution units(“EUs”) 2452A-2452N and media/texture samplers 2454A-2454N. In at leastone embodiment, each sub-core in second sub-cores 2460A-2460N includesat least a second set of execution units 2462A-2462N and samplers2464A-2464N. In at least one embodiment, each sub-core 2450A-2450N,2460A-2460N shares a set of shared resources 2470A-2470N. In at leastone embodiment, shared resources 2470 include shared cache memory andpixel operation logic.

FIG. 25 illustrates a processor 2500, in accordance with at least oneembodiment. In at least one embodiment, processor 2500 may include,without limitation, logic circuits to perform instructions. In at leastone embodiment, processor 2500 may perform instructions, including x86instructions, ARM instructions, specialized instructions for ASICs, etc.In at least one embodiment, processor 2510 may include registers tostore packed data, such as 64-bit wide MMX™ registers in microprocessorsenabled with MMX technology from Intel Corporation of Santa Clara,Calif. In at least one embodiment, MMX registers, available in bothinteger and floating point forms, may operate with packed data elementsthat accompany SIMD and streaming SIMD extensions (“SSE”) instructions.In at least one embodiment, 128-bit wide XMM registers relating to SSE2,SSE3, SSE4, AVX, or beyond (referred to generically as “SSEx”)technology may hold such packed data operands. In at least oneembodiment, processors 2510 may perform instructions to accelerate CUDAprograms.

In at least one embodiment, processor 2500 includes an in-order frontend (“front end”) 2501 to fetch instructions to be executed and prepareinstructions to be used later in processor pipeline. In at least oneembodiment, front end 2501 may include several units. In at least oneembodiment, an instruction prefetcher 2526 fetches instructions frommemory and feeds instructions to an instruction decoder 2528 which inturn decodes or interprets instructions. For example, in at least oneembodiment, instruction decoder 2528 decodes a received instruction intoone or more operations called “micro-instructions” or “micro-operations”(also called “micro ops” or “uops”) for execution. In at least oneembodiment, instruction decoder 2528 parses instruction into an opcodeand corresponding data and control fields that may be used bymicro-architecture to perform operations. In at least one embodiment, atrace cache 2530 may assemble decoded uops into program orderedsequences or traces in a uop queue 2534 for execution. In at least oneembodiment, when trace cache 2530 encounters a complex instruction, amicrocode ROM 2532 provides uops needed to complete an operation.

In at least one embodiment, some instructions may be converted into asingle micro-op, whereas others need several micro-ops to complete fulloperation. In at least one embodiment, if more than four micro-ops areneeded to complete an instruction, instruction decoder 2528 may accessmicrocode ROM 2532 to perform instruction. In at least one embodiment,an instruction may be decoded into a small number of micro-ops forprocessing at instruction decoder 2528. In at least one embodiment, aninstruction may be stored within microcode ROM 2532 should a number ofmicro-ops be needed to accomplish operation. In at least one embodiment,trace cache 2530 refers to an entry point programmable logic array(“PLA”) to determine a correct micro-instruction pointer for readingmicrocode sequences to complete one or more instructions from microcodeROM 2532. In at least one embodiment, after microcode ROM 2532 finishessequencing micro-ops for an instruction, front end 2501 of machine mayresume fetching micro-ops from trace cache 2530.

In at least one embodiment, out-of-order execution engine (“out of orderengine”) 2503 may prepare instructions for execution. In at least oneembodiment, out-of-order execution logic has a number of buffers tosmooth out and re-order the flow of instructions to optimize performanceas they go down a pipeline and get scheduled for execution. Out-of-orderexecution engine 2503 includes, without limitation, anallocator/register renamer 2540, a memory uop queue 2542, aninteger/floating point uop queue 2544, a memory scheduler 2546, a fastscheduler 2502, a slow/general floating point scheduler (“slow/generalFP scheduler”) 2504, and a simple floating point scheduler (“simple FPscheduler”) 2506. In at least one embodiment, fast schedule 2502,slow/general floating point scheduler 2504, and simple floating pointscheduler 2506 are also collectively referred to herein as “uopschedulers 2502, 2504, 2506.” Allocator/register renamer 2540 allocatesmachine buffers and resources that each uop needs in order to execute.In at least one embodiment, allocator/register renamer 2540 renameslogic registers onto entries in a register file. In at least oneembodiment, allocator/register renamer 2540 also allocates an entry foreach uop in one of two uop queues, memory uop queue 2542 for memoryoperations and integer/floating point uop queue 2544 for non-memoryoperations, in front of memory scheduler 2546 and uop schedulers 2502,2504, 2506. In at least one embodiment, uop schedulers 2502, 2504, 2506,determine when a uop is ready to execute based on readiness of theirdependent input register operand sources and availability of executionresources uops need to complete their operation. In at least oneembodiment, fast scheduler 2502 of at least one embodiment may scheduleon each half of main clock cycle while slow/general floating pointscheduler 2504 and simple floating point scheduler 2506 may scheduleonce per main processor clock cycle. In at least one embodiment, uopschedulers 2502, 2504, 2506 arbitrate for dispatch ports to scheduleuops for execution.

In at least one embodiment, execution block 2511 includes, withoutlimitation, an integer register file/bypass network 2508, a floatingpoint register file/bypass network (“FP register file/bypass network”)2510, address generation units (“AGUs”) 2512 and 2514, fast ALUs 2516and 2518, a slow ALU 2520, a floating point ALU (“FP”) 2522, and afloating point move unit (“FP move”) 2524. In at least one embodiment,integer register file/bypass network 2508 and floating point registerfile/bypass network 2510 are also referred to herein as “register files2508, 2510.” In at least one embodiment, AGUSs 2512 and 2514, fast ALUs2516 and 2518, slow ALU 2520, floating point ALU 2522, and floatingpoint move unit 2524 are also referred to herein as “execution units2512, 2514, 2516, 2518, 2520, 2522, and 2524.” In at least oneembodiment, an execution block may include, without limitation, anynumber (including zero) and type of register files, bypass networks,address generation units, and execution units, in any combination.

In at least one embodiment, register files 2508, 2510 may be arrangedbetween uop schedulers 2502, 2504, 2506, and execution units 2512, 2514,2516, 2518, 2520, 2522, and 2524. In at least one embodiment, integerregister file/bypass network 2508 performs integer operations. In atleast one embodiment, floating point register file/bypass network 2510performs floating point operations. In at least one embodiment, each ofregister files 2508, 2510 may include, without limitation, a bypassnetwork that may bypass or forward just completed results that have notyet been written into register file to new dependent uops. In at leastone embodiment, register files 2508, 2510 may communicate data with eachother. In at least one embodiment, integer register file/bypass network2508 may include, without limitation, two separate register files, oneregister file for low-order thirty-two bits of data and a secondregister file for high order thirty-two bits of data. In at least oneembodiment, floating point register file/bypass network 2510 mayinclude, without limitation, 128-bit wide entries because floating pointinstructions typically have operands from 64 to 128 bits in width.

In at least one embodiment, execution units 2512, 2514, 2516, 2518,2520, 2522, 2524 may execute instructions. In at least one embodiment,register files 2508, 2510 store integer and floating point data operandvalues that micro-instructions need to execute. In at least oneembodiment, processor 2500 may include, without limitation, any numberand combination of execution units 2512, 2514, 2516, 2518, 2520, 2522,2524. In at least one embodiment, floating point ALU 2522 and floatingpoint move unit 2524 may execute floating point, MMX, SIMD, AVX and SSE,or other operations. In at least one embodiment, floating point ALU 2522may include, without limitation, a 64-bit by 64-bit floating pointdivider to execute divide, square root, and remainder micro ops. In atleast one embodiment, instructions involving a floating point value maybe handled with floating point hardware. In at least one embodiment, ALUoperations may be passed to fast ALUs 2516, 2518. In at least oneembodiment, fast ALUS 2516, 2518 may execute fast operations with aneffective latency of half a clock cycle. In at least one embodiment,most complex integer operations go to slow ALU 2520 as slow ALU 2520 mayinclude, without limitation, integer execution hardware for long-latencytype of operations, such as a multiplier, shifts, flag logic, and branchprocessing. In at least one embodiment, memory load/store operations maybe executed by AGUs 2512, 2514. In at least one embodiment, fast ALU2516, fast ALU 2518, and slow ALU 2520 may perform integer operations on64-bit data operands. In at least one embodiment, fast ALU 2516, fastALU 2518, and slow ALU 2520 may be implemented to support a variety ofdata bit sizes including sixteen, thirty-two, 128, 256, etc. In at leastone embodiment, floating point ALU 2522 and floating point move unit2524 may be implemented to support a range of operands having bits ofvarious widths. In at least one embodiment, floating point ALU 2522 andfloating point move unit 2524 may operate on 128-bit wide packed dataoperands in conjunction with SIMD and multimedia instructions.

In at least one embodiment, uop schedulers 2502, 2504, 2506 dispatchdependent operations before parent load has finished executing. In atleast one embodiment, as uops may be speculatively scheduled andexecuted in processor 2500, processor 2500 may also include logic tohandle memory misses. In at least one embodiment, if a data load missesin a data cache, there may be dependent operations in flight in pipelinethat have left a scheduler with temporarily incorrect data. In at leastone embodiment, a replay mechanism tracks and re-executes instructionsthat use incorrect data. In at least one embodiment, dependentoperations might need to be replayed and independent ones may be allowedto complete. In at least one embodiment, schedulers and replaymechanisms of at least one embodiment of a processor may also bedesigned to catch instruction sequences for text string comparisonoperations.

In at least one embodiment, the term “registers” may refer to on-boardprocessor storage locations that may be used as part of instructions toidentify operands. In at least one embodiment, registers may be thosethat may be usable from outside of a processor (from a programmer'sperspective). In at least one embodiment, registers might not be limitedto a particular type of circuit. Rather, in at least one embodiment, aregister may store data, provide data, and perform functions describedherein. In at least one embodiment, registers described herein may beimplemented by circuitry within a processor using any number ofdifferent techniques, such as dedicated physical registers, dynamicallyallocated physical registers using register renaming, combinations ofdedicated and dynamically allocated physical registers, etc. In at leastone embodiment, integer registers store 32-bit integer data. A registerfile of at least one embodiment also contains eight multimedia SIMDregisters for packed data.

FIG. 26 illustrates a processor 2600, in accordance with at least oneembodiment. In at least one embodiment, processor 2600 includes, withoutlimitation, one or more processor cores (“cores”) 2602A-2602N, anintegrated memory controller 2614, and an integrated graphics processor2608. In at least one embodiment, processor 2600 can include additionalcores up to and including additional processor core 2602N represented bydashed lined boxes. In at least one embodiment, each of processor cores2602A-2602N includes one or more internal cache units 2604A-2604N. In atleast one embodiment, each processor core also has access to one or moreshared cached units 2606.

In at least one embodiment, internal cache units 2604A-2604N and sharedcache units 2606 represent a cache memory hierarchy within processor2600. In at least one embodiment, cache memory units 2604A-2604N mayinclude at least one level of instruction and data cache within eachprocessor core and one or more levels of shared mid-level cache, such asan L2, L3, Level 4 (“L4”), or other levels of cache, where a highestlevel of cache before external memory is classified as an LLC. In atleast one embodiment, cache coherency logic maintains coherency betweenvarious cache units 2606 and 2604A-2604N.

In at least one embodiment, processor 2600 may also include a set of oneor more bus controller units 2616 and a system agent core 2610. In atleast one embodiment, one or more bus controller units 2616 manage a setof peripheral buses, such as one or more PCI or PCI express buses. In atleast one embodiment, system agent core 2610 provides managementfunctionality for various processor components. In at least oneembodiment, system agent core 2610 includes one or more integratedmemory controllers 2614 to manage access to various external memorydevices (not shown).

In at least one embodiment, one or more of processor cores 2602A-2602Ninclude support for simultaneous multi-threading. In at least oneembodiment, system agent core 2610 includes components for coordinatingand operating processor cores 2602A-2602N during multi-threadedprocessing. In at least one embodiment, system agent core 2610 mayadditionally include a power control unit (“PCU”), which includes logicand components to regulate one or more power states of processor cores2602A-2602N and graphics processor 2608.

In at least one embodiment, processor 2600 additionally includesgraphics processor 2608 to execute graphics processing operations. In atleast one embodiment, graphics processor 2608 couples with shared cacheunits 2606, and system agent core 2610, including one or more integratedmemory controllers 2614. In at least one embodiment, system agent core2610 also includes a display controller 2611 to drive graphics processoroutput to one or more coupled displays. In at least one embodiment,display controller 2611 may also be a separate module coupled withgraphics processor 2608 via at least one interconnect, or may beintegrated within graphics processor 2608.

In at least one embodiment, a ring based interconnect unit 2612 is usedto couple internal components of processor 2600. In at least oneembodiment, an alternative interconnect unit may be used, such as apoint-to-point interconnect, a switched interconnect, or othertechniques. In at least one embodiment, graphics processor 2608 coupleswith ring interconnect 2612 via an I/O link 2613.

In at least one embodiment, I/O link 2613 represents at least one ofmultiple varieties of I/O interconnects, including an on package I/Ointerconnect which facilitates communication between various processorcomponents and a high-performance embedded memory module 2618, such asan eDRAM module. In at least one embodiment, each of processor cores2602A-2602N and graphics processor 2608 use embedded memory modules 2618as a shared LLC.

In at least one embodiment, processor cores 2602A-2602N are homogeneouscores executing a common instruction set architecture. In at least oneembodiment, processor cores 2602A-2602N are heterogeneous in terms ofISA, where one or more of processor cores 2602A-2602N execute a commoninstruction set, while one or more other cores of processor cores2602A-26-02N executes a subset of a common instruction set or adifferent instruction set. In at least one embodiment, processor cores2602A-2602N are heterogeneous in terms of microarchitecture, where oneor more cores having a relatively higher power consumption couple withone or more cores having a lower power consumption. In at least oneembodiment, processor 2600 can be implemented on one or more chips or asan SoC integrated circuit.

FIG. 27 illustrates a graphics processor core 2700, in accordance withat least one embodiment described. In at least one embodiment, graphicsprocessor core 2700 is included within a graphics core array. In atleast one embodiment, graphics processor core 2700, sometimes referredto as a core slice, can be one or multiple graphics cores within amodular graphics processor. In at least one embodiment, graphicsprocessor core 2700 is exemplary of one graphics core slice, and agraphics processor as described herein may include multiple graphicscore slices based on target power and performance envelopes. In at leastone embodiment, each graphics core 2700 can include a fixed functionblock 2730 coupled with multiple sub-cores 2701A-2701F, also referred toas sub-slices, that include modular blocks of general-purpose and fixedfunction logic.

In at least one embodiment, fixed function block 2730 includes ageometry/fixed function pipeline 2736 that can be shared by allsub-cores in graphics processor 2700, for example, in lower performanceand/or lower power graphics processor implementations. In at least oneembodiment, geometry/fixed function pipeline 2736 includes a 3D fixedfunction pipeline, a video front-end unit, a thread spawner and threaddispatcher, and a unified return buffer manager, which manages unifiedreturn buffers.

In at least one embodiment, fixed function block 2730 also includes agraphics SoC interface 2737, a graphics microcontroller 2738, and amedia pipeline 2739. Graphics SoC interface 2737 provides an interfacebetween graphics core 2700 and other processor cores within an SoCintegrated circuit. In at least one embodiment, graphics microcontroller2738 is a programmable sub-processor that is configurable to managevarious functions of graphics processor 2700, including thread dispatch,scheduling, and pre-emption. In at least one embodiment, media pipeline2739 includes logic to facilitate decoding, encoding, pre-processing,and/or post-processing of multimedia data, including image and videodata. In at least one embodiment, media pipeline 2739 implements mediaoperations via requests to compute or sampling logic within sub-cores2701-2701F.

In at least one embodiment, SoC interface 2737 enables graphics core2700 to communicate with general-purpose application processor cores(e.g., CPUs) and/or other components within an SoC, including memoryhierarchy elements such as a shared LLC memory, system RAM, and/orembedded on-chip or on-package DRAM. In at least one embodiment, SoCinterface 2737 can also enable communication with fixed function deviceswithin an SoC, such as camera imaging pipelines, and enables use ofand/or implements global memory atomics that may be shared betweengraphics core 2700 and CPUs within an SoC. In at least one embodiment,SoC interface 2737 can also implement power management controls forgraphics core 2700 and enable an interface between a clock domain ofgraphic core 2700 and other clock domains within an SoC. In at least oneembodiment, SoC interface 2737 enables receipt of command buffers from acommand streamer and global thread dispatcher that are configured toprovide commands and instructions to each of one or more graphics coreswithin a graphics processor. In at least one embodiment, commands andinstructions can be dispatched to media pipeline 2739, when mediaoperations are to be performed, or a geometry and fixed functionpipeline (e.g., geometry and fixed function pipeline 2736, geometry andfixed function pipeline 2714) when graphics processing operations are tobe performed.

In at least one embodiment, graphics microcontroller 2738 can beconfigured to perform various scheduling and management tasks forgraphics core 2700. In at least one embodiment, graphics microcontroller2738 can perform graphics and/or compute workload scheduling on variousgraphics parallel engines within execution unit (EU) arrays 2702A-2702F,2704A-2704F within sub-cores 2701A-2701F. In at least one embodiment,host software executing on a CPU core of an SoC including graphics core2700 can submit workloads one of multiple graphic processor doorbells,which invokes a scheduling operation on an appropriate graphics engine.In at least one embodiment, scheduling operations include determiningwhich workload to run next, submitting a workload to a command streamer,pre-empting existing workloads running on an engine, monitoring progressof a workload, and notifying host software when a workload is complete.In at least one embodiment, graphics microcontroller 2738 can alsofacilitate low-power or idle states for graphics core 2700, providinggraphics core 2700 with an ability to save and restore registers withingraphics core 2700 across low-power state transitions independently froman operating system and/or graphics driver software on a system.

In at least one embodiment, graphics core 2700 may have greater than orfewer than illustrated sub-cores 2701A-2701F, up to N modular sub-cores.For each set of N sub-cores, in at least one embodiment, graphics core2700 can also include shared function logic 2710, shared and/or cachememory 2712, a geometry/fixed function pipeline 2714, as well asadditional fixed function logic 2716 to accelerate various graphics andcompute processing operations. In at least one embodiment, sharedfunction logic 2710 can include logic units (e.g., sampler, math, and/orinter-thread communication logic) that can be shared by each N sub-coreswithin graphics core 2700. Shared and/or cache memory 2712 can be an LLCfor N sub-cores 2701A-2701F within graphics core 2700 and can also serveas shared memory that is accessible by multiple sub-cores. In at leastone embodiment, geometry/fixed function pipeline 2714 can be includedinstead of geometry/fixed function pipeline 2736 within fixed functionblock 2730 and can include same or similar logic units.

In at least one embodiment, graphics core 2700 includes additional fixedfunction logic 2716 that can include various fixed function accelerationlogic for use by graphics core 2700. In at least one embodiment,additional fixed function logic 2716 includes an additional geometrypipeline for use in position only shading. In position-only shading, atleast two geometry pipelines exist, whereas in a full geometry pipelinewithin geometry/fixed function pipeline 2716, 2736, and a cull pipeline,which is an additional geometry pipeline which may be included withinadditional fixed function logic 2716. In at least one embodiment, cullpipeline is a trimmed down version of a full geometry pipeline. In atleast one embodiment, a full pipeline and a cull pipeline can executedifferent instances of an application, each instance having a separatecontext. In at least one embodiment, position only shading can hide longcull runs of discarded triangles, enabling shading to be completedearlier in some instances. For example, in at least one embodiment, cullpipeline logic within additional fixed function logic 2716 can executeposition shaders in parallel with a main application and generallygenerates critical results faster than a full pipeline, as a cullpipeline fetches and shades position attribute of vertices, withoutperforming rasterization and rendering of pixels to a frame buffer. Inat least one embodiment, a cull pipeline can use generated criticalresults to compute visibility information for all triangles withoutregard to whether those triangles are culled. In at least oneembodiment, a full pipeline (which in this instance may be referred toas a replay pipeline) can consume visibility information to skip culledtriangles to shade only visible triangles that are finally passed to arasterization phase.

In at least one embodiment, additional fixed function logic 2716 canalso include general purpose processing acceleration logic, such asfixed function matrix multiplication logic, for accelerating CUDAprograms.

In at least one embodiment, each graphics sub-core 2701A-2701F includesa set of execution resources that may be used to perform graphics,media, and compute operations in response to requests by graphicspipeline, media pipeline, or shader programs. In at least oneembodiment, graphics sub-cores 2701A-2701F include multiple EU arrays2702A-2702F, 2704A-2704F, thread dispatch and inter-thread communication(“TD/IC”) logic 2703A-2703F, a 3D (e.g., texture) sampler 2705A-2705F, amedia sampler 2706A-2706F, a shader processor 2707A-2707F, and sharedlocal memory (“SLM”) 2708A-2708F. EU arrays 2702A-2702F, 2704A-2704Feach include multiple execution units, which are GPGPUs capable ofperforming floating-point and integer/fixed-point logic operations inservice of a graphics, media, or compute operation, including graphics,media, or compute shader programs. In at least one embodiment, TD/IClogic 2703A-2703F performs local thread dispatch and thread controloperations for execution units within a sub-core and facilitatecommunication between threads executing on execution units of asub-core. In at least one embodiment, 3D sampler 2705A-2705F can readtexture or other 3D graphics related data into memory. In at least oneembodiment, 3D sampler can read texture data differently based on aconfigured sample state and texture format associated with a giventexture. In at least one embodiment, media sampler 2706A-2706F canperform similar read operations based on a type and format associatedwith media data. In at least one embodiment, each graphics sub-core2701A-2701F can alternately include a unified 3D and media sampler. Inat least one embodiment, threads executing on execution units withineach of sub-cores 2701A-2701F can make use of shared local memory2708A-2708F within each sub-core, to enable threads executing within athread group to execute using a common pool of on-chip memory.

FIG. 28 illustrates a parallel processing unit (“PPU”) 2800, inaccordance with at least one embodiment. In at least one embodiment, PPU2800 is configured with machine-readable code that, if executed by PPU2800, causes PPU 2800 to perform some or all of processes and techniquesdescribed herein. In at least one embodiment, PPU 2800 is amulti-threaded processor that is implemented on one or more integratedcircuit devices and that utilizes multithreading as a latency-hidingtechnique designed to process computer-readable instructions (alsoreferred to as machine-readable instructions or simply instructions) onmultiple threads in parallel. In at least one embodiment, a threadrefers to a thread of execution and is an instantiation of a set ofinstructions configured to be executed by PPU 2800. In at least oneembodiment, PPU 2800 is a GPU configured to implement a graphicsrendering pipeline for processing three-dimensional (“3D”) graphics datain order to generate two-dimensional (“2D”) image data for display on adisplay device such as an LCD device. In at least one embodiment, PPU2800 is utilized to perform computations such as linear algebraoperations and machine-learning operations. FIG. 28 illustrates anexample parallel processor for illustrative purposes only and should beconstrued as a non-limiting example of a processor architecture that maybe implemented in at least one embodiment.

In at least one embodiment, one or more PPUs 2800 are configured toaccelerate High Performance Computing (“HPC”), data center, and machinelearning applications. In at least one embodiment, one or more PPUs 2800are configured to accelerate CUDA programs. In at least one embodiment,PPU 2800 includes, without limitation, an I/O unit 2806, a front-endunit 2810, a scheduler unit 2812, a work distribution unit 2814, a hub2816, a crossbar (“Xbar”) 2820, one or more general processing clusters(“GPCs”) 2818, and one or more partition units (“memory partitionunits”) 2822. In at least one embodiment, PPU 2800 is connected to ahost processor or other PPUs 2800 via one or more high-speed GPUinterconnects (“GPU interconnects”) 2808. In at least one embodiment,PPU 2800 is connected to a host processor or other peripheral devicesvia a system bus or interconnect 2802. In at least one embodiment, PPU2800 is connected to a local memory comprising one or more memorydevices (“memory”) 2804. In at least one embodiment, memory devices 2804include, without limitation, one or more dynamic random access memory(DRAM) devices. In at least one embodiment, one or more DRAM devices areconfigured and/or configurable as high-bandwidth memory (“HBM”)subsystems, with multiple DRAM dies stacked within each device.

In at least one embodiment, high-speed GPU interconnect 2808 may referto a wire-based multi-lane communications link that is used by systemsto scale and include one or more PPUs 2800 combined with one or moreCPUs, supports cache coherence between PPUs 2800 and CPUs, and CPUmastering. In at least one embodiment, data and/or commands aretransmitted by high-speed GPU interconnect 2808 through hub 2816 to/fromother units of PPU 2800 such as one or more copy engines, videoencoders, video decoders, power management units, and other componentswhich may not be explicitly illustrated in FIG. 28 .

In at least one embodiment, I/O unit 2806 is configured to transmit andreceive communications (e.g., commands, data) from a host processor (notillustrated in FIG. 28 ) over system bus 2802. In at least oneembodiment, I/O unit 2806 communicates with host processor directly viasystem bus 2802 or through one or more intermediate devices such as amemory bridge. In at least one embodiment, I/O unit 2806 may communicatewith one or more other processors, such as one or more of PPUs 2800 viasystem bus 2802. In at least one embodiment, I/O unit 2806 implements aPCIe interface for communications over a PCIe bus. In at least oneembodiment, I/O unit 2806 implements interfaces for communicating withexternal devices.

In at least one embodiment, I/O unit 2806 decodes packets received viasystem bus 2802. In at least one embodiment, at least some packetsrepresent commands configured to cause PPU 2800 to perform variousoperations. In at least one embodiment, I/O unit 2806 transmits decodedcommands to various other units of PPU 2800 as specified by commands. Inat least one embodiment, commands are transmitted to front-end unit 2810and/or transmitted to hub 2816 or other units of PPU 2800 such as one ormore copy engines, a video encoder, a video decoder, a power managementunit, etc. (not explicitly illustrated in FIG. 28 ). In at least oneembodiment, I/O unit 2806 is configured to route communications betweenand among various logical units of PPU 2800.

In at least one embodiment, a program executed by host processor encodesa command stream in a buffer that provides workloads to PPU 2800 forprocessing. In at least one embodiment, a workload comprisesinstructions and data to be processed by those instructions. In at leastone embodiment, buffer is a region in a memory that is accessible (e.g.,read/write) by both a host processor and PPU 2800—a host interface unitmay be configured to access buffer in a system memory connected tosystem bus 2802 via memory requests transmitted over system bus 2802 byI/O unit 2806. In at least one embodiment, a host processor writes acommand stream to a buffer and then transmits a pointer to the start ofthe command stream to PPU 2800 such that front-end unit 2810 receivespointers to one or more command streams and manages one or more commandstreams, reading commands from command streams and forwarding commandsto various units of PPU 2800.

In at least one embodiment, front-end unit 2810 is coupled to schedulerunit 2812 that configures various GPCs 2818 to process tasks defined byone or more command streams. In at least one embodiment, scheduler unit2812 is configured to track state information related to various tasksmanaged by scheduler unit 2812 where state information may indicatewhich of GPCs 2818 a task is assigned to, whether task is active orinactive, a priority level associated with task, and so forth. In atleast one embodiment, scheduler unit 2812 manages execution of aplurality of tasks on one or more of GPCs 2818.

In at least one embodiment, scheduler unit 2812 is coupled to workdistribution unit 2814 that is configured to dispatch tasks forexecution on GPCs 2818. In at least one embodiment, work distributionunit 2814 tracks a number of scheduled tasks received from schedulerunit 2812 and work distribution unit 2814 manages a pending task pooland an active task pool for each of GPCs 2818. In at least oneembodiment, pending task pool comprises a number of slots (e.g., 32slots) that contain tasks assigned to be processed by a particular GPC2818; active task pool may comprise a number of slots (e.g., 4 slots)for tasks that are actively being processed by GPCs 2818 such that asone of GPCs 2818 completes execution of a task, that task is evictedfrom active task pool for GPC 2818 and one of other tasks from pendingtask pool is selected and scheduled for execution on GPC 2818. In atleast one embodiment, if an active task is idle on GPC 2818, such aswhile waiting for a data dependency to be resolved, then the active taskis evicted from GPC 2818 and returned to a pending task pool whileanother task in the pending task pool is selected and scheduled forexecution on GPC 2818.

In at least one embodiment, work distribution unit 2814 communicateswith one or more GPCs 2818 via XBar 2820. In at least one embodiment,XBar 2820 is an interconnect network that couples many units of PPU 2800to other units of PPU 2800 and can be configured to couple workdistribution unit 2814 to a particular GPC 2818. In at least oneembodiment, one or more other units of PPU 2800 may also be connected toXBar 2820 via hub 2816.

In at least one embodiment, tasks are managed by scheduler unit 2812 anddispatched to one of GPCs 2818 by work distribution unit 2814. GPC 2818is configured to process task and generate results. In at least oneembodiment, results may be consumed by other tasks within GPC 2818,routed to a different GPC 2818 via XBar 2820, or stored in memory 2804.In at least one embodiment, results can be written to memory 2804 viapartition units 2822, which implement a memory interface for reading andwriting data to/from memory 2804. In at least one embodiment, resultscan be transmitted to another PPU 2804 or CPU via high-speed GPUinterconnect 2808. In at least one embodiment, PPU 2800 includes,without limitation, a number U of partition units 2822 that is equal tonumber of separate and distinct memory devices 2804 coupled to PPU 2800.

In at least one embodiment, a host processor executes a driver kernelthat implements an application programming interface (“API”) thatenables one or more applications executing on host processor to scheduleoperations for execution on PPU 2800. In at least one embodiment,multiple compute applications are simultaneously executed by PPU 2800and PPU 2800 provides isolation, quality of service (“QoS”), andindependent address spaces for multiple compute applications. In atleast one embodiment, an application generates instructions (e.g., inthe form of API calls) that cause a driver kernel to generate one ormore tasks for execution by PPU 2800 and the driver kernel outputs tasksto one or more streams being processed by PPU 2800. In at least oneembodiment, each task comprises one or more groups of related threads,which may be referred to as a warp. In at least one embodiment, a warpcomprises a plurality of related threads (e.g., 32 threads) that can beexecuted in parallel. In at least one embodiment, cooperating threadscan refer to a plurality of threads including instructions to perform atask and that exchange data through shared memory.

FIG. 29 illustrates a GPC 2900, in accordance with at least oneembodiment. In at least one embodiment, GPC 2900 is GPC 2818 of FIG. 28. In at least one embodiment, each GPC 2900 includes, withoutlimitation, a number of hardware units for processing tasks and each GPC2900 includes, without limitation, a pipeline manager 2902, a pre-rasteroperations unit (“PROP”) 2904, a raster engine 2908, a work distributioncrossbar (“WDX”) 2916, an MMU 2918, one or more Data Processing Clusters(“DPCs”) 2906, and any suitable combination of parts.

In at least one embodiment, operation of GPC 2900 is controlled bypipeline manager 2902. In at least one embodiment, pipeline manager 2902manages configuration of one or more DPCs 2906 for processing tasksallocated to GPC 2900. In at least one embodiment, pipeline manager 2902configures at least one of one or more DPCs 2906 to implement at least aportion of a graphics rendering pipeline. In at least one embodiment,DPC 2906 is configured to execute a vertex shader program on aprogrammable streaming multiprocessor (“SM”) 2914. In at least oneembodiment, pipeline manager 2902 is configured to route packetsreceived from a work distribution unit to appropriate logical unitswithin GPC 2900 and, in at least one embodiment, some packets may berouted to fixed function hardware units in PROP 2904 and/or rasterengine 2908 while other packets may be routed to DPCs 2906 forprocessing by a primitive engine 2912 or SM 2914. In at least oneembodiment, pipeline manager 2902 configures at least one of DPCs 2906to implement a computing pipeline. In at least one embodiment, pipelinemanager 2902 configures at least one of DPCs 2906 to execute at least aportion of a CUDA program.

In at least one embodiment, PROP unit 2904 is configured to route datagenerated by raster engine 2908 and DPCs 2906 to a Raster Operations(“ROP”) unit in a partition unit, such as memory partition unit 2822described in more detail above in conjunction with FIG. 28 . In at leastone embodiment, PROP unit 2904 is configured to perform optimizationsfor color blending, organize pixel data, perform address translations,and more. In at least one embodiment, raster engine 2908 includes,without limitation, a number of fixed function hardware units configuredto perform various raster operations and, in at least one embodiment,raster engine 2908 includes, without limitation, a setup engine, acoarse raster engine, a culling engine, a clipping engine, a fine rasterengine, a tile coalescing engine, and any suitable combination thereof.In at least one embodiment, a setup engine receives transformed verticesand generates plane equations associated with geometric primitivedefined by vertices; plane equations are transmitted to a coarse rasterengine to generate coverage information (e.g., an x, y coverage mask fora tile) for a primitive; the output of the coarse raster engine istransmitted to a culling engine where fragments associated with aprimitive that fail a z-test are culled, and transmitted to a clippingengine where fragments lying outside a viewing frustum are clipped. Inat least one embodiment, fragments that survive clipping and culling arepassed to a fine raster engine to generate attributes for pixelfragments based on plane equations generated by a setup engine. In atleast one embodiment, the output of raster engine 2908 comprisesfragments to be processed by any suitable entity such as by a fragmentshader implemented within DPC 2906.

In at least one embodiment, each DPC 2906 included in GPC 2900 comprise,without limitation, an M-Pipe Controller (“MPC”) 2910; primitive engine2912; one or more SMs 2914; and any suitable combination thereof. In atleast one embodiment, MPC 2910 controls operation of DPC 2906, routingpackets received from pipeline manager 2902 to appropriate units in DPC2906. In at least one embodiment, packets associated with a vertex arerouted to primitive engine 2912, which is configured to fetch vertexattributes associated with vertex from memory; in contrast, packetsassociated with a shader program may be transmitted to SM 2914.

In at least one embodiment, SM 2914 comprises, without limitation, aprogrammable streaming processor that is configured to process tasksrepresented by a number of threads. In at least one embodiment, SM 2914is multi-threaded and configured to execute a plurality of threads(e.g., 32 threads) from a particular group of threads concurrently andimplements a SIMD architecture where each thread in a group of threads(e.g., a warp) is configured to process a different set of data based onsame set of instructions. In at least one embodiment, all threads ingroup of threads execute same instructions. In at least one embodiment,SM 2914 implements a SIMT architecture wherein each thread in a group ofthreads is configured to process a different set of data based on sameset of instructions, but where individual threads in group of threadsare allowed to diverge during execution. In at least one embodiment, aprogram counter, a call stack, and an execution state is maintained foreach warp, enabling concurrency between warps and serial executionwithin warps when threads within a warp diverge. In another embodiment,a program counter, a call stack, and an execution state is maintainedfor each individual thread, enabling equal concurrency between allthreads, within and between warps. In at least one embodiment, anexecution state is maintained for each individual thread and threadsexecuting the same instructions may be converged and executed inparallel for better efficiency. At least one embodiment of SM 2914 isdescribed in more detail in conjunction with FIG. 30 .

In at least one embodiment, MMU 2918 provides an interface between GPC2900 and a memory partition unit (e.g., partition unit 2822 of FIG. 28 )and MMU 2918 provides translation of virtual addresses into physicaladdresses, memory protection, and arbitration of memory requests. In atleast one embodiment, MMU 2918 provides one or more translationlookaside buffers (TLBs) for performing translation of virtual addressesinto physical addresses in memory.

FIG. 30 illustrates a streaming multiprocessor (“SM”) 3000, inaccordance with at least one embodiment. In at least one embodiment, SM3000 is SM 2914 of FIG. 29 . In at least one embodiment, SM 3000includes, without limitation, an instruction cache 3002; one or morescheduler units 3004; a register file 3008; one or more processing cores(“cores”) 3010; one or more special function units (“SFUs”) 3012; one ormore LSUs 3014; an interconnect network 3016; a shared memory/L1 cache3018; and any suitable combination thereof. In at least one embodiment,a work distribution unit dispatches tasks for execution on GPCs ofparallel processing units (PPUs) and each task is allocated to aparticular Data Processing Cluster (DPC) within a GPC and, if a task isassociated with a shader program, then the task is allocated to one ofSMs 3000. In at least one embodiment, scheduler unit 3004 receives tasksfrom a work distribution unit and manages instruction scheduling for oneor more thread blocks assigned to SM 3000. In at least one embodiment,scheduler unit 3004 schedules thread blocks for execution as warps ofparallel threads, wherein each thread block is allocated at least onewarp. In at least one embodiment, each warp executes threads. In atleast one embodiment, scheduler unit 3004 manages a plurality ofdifferent thread blocks, allocating warps to different thread blocks andthen dispatching instructions from a plurality of different cooperativegroups to various functional units (e.g., processing cores 3010, SFUs3012, and LSUs 3014) during each clock cycle.

In at least one embodiment, “cooperative groups” may refer to aprogramming model for organizing groups of communicating threads thatallows developers to express granularity at which threads arecommunicating, enabling expression of richer, more efficient paralleldecompositions. In at least one embodiment, cooperative launch APIssupport synchronization amongst thread blocks for execution of parallelalgorithms. In at least one embodiment, APIs of conventional programmingmodels provide a single, simple construct for synchronizing cooperatingthreads: a barrier across all threads of a thread block (e.g.,syncthreads( ) function). However, in at least one embodiment,programmers may define groups of threads at smaller than thread blockgranularities and synchronize within defined groups to enable greaterperformance, design flexibility, and software reuse in the form ofcollective group-wide function interfaces. In at least one embodiment,cooperative groups enable programmers to define groups of threadsexplicitly at sub-block and multi-block granularities, and to performcollective operations such as synchronization on threads in acooperative group. In at least one embodiment, a sub-block granularityis as small as a single thread. In at least one embodiment, aprogramming model supports clean composition across software boundaries,so that libraries and utility functions can synchronize safely withintheir local context without having to make assumptions aboutconvergence. In at least one embodiment, cooperative group primitivesenable new patterns of cooperative parallelism, including, withoutlimitation, producer-consumer parallelism, opportunistic parallelism,and global synchronization across an entire grid of thread blocks.

In at least one embodiment, a dispatch unit 3006 is configured totransmit instructions to one or more of functional units and schedulerunit 3004 includes, without limitation, two dispatch units 3006 thatenable two different instructions from same warp to be dispatched duringeach clock cycle. In at least one embodiment, each scheduler unit 3004includes a single dispatch unit 3006 or additional dispatch units 3006.

In at least one embodiment, each SM 3000, in at least one embodiment,includes, without limitation, register file 3008 that provides a set ofregisters for functional units of SM 3000. In at least one embodiment,register file 3008 is divided between each of the functional units suchthat each functional unit is allocated a dedicated portion of registerfile 3008. In at least one embodiment, register file 3008 is dividedbetween different warps being executed by SM 3000 and register file 3008provides temporary storage for operands connected to data paths offunctional units. In at least one embodiment, each SM 3000 comprises,without limitation, a plurality of L processing cores 3010. In at leastone embodiment, SM 3000 includes, without limitation, a large number(e.g., 128 or more) of distinct processing cores 3010. In at least oneembodiment, each processing core 3010 includes, without limitation, afully-pipelined, single-precision, double-precision, and/or mixedprecision processing unit that includes, without limitation, a floatingpoint arithmetic logic unit and an integer arithmetic logic unit. In atleast one embodiment, floating point arithmetic logic units implementIEEE 754-2008 standard for floating point arithmetic. In at least oneembodiment, processing cores 3010 include, without limitation, 64single-precision (32-bit) floating point cores, 64 integer cores, 32double-precision (64-bit) floating point cores, and 8 tensor cores.

In at least one embodiment, tensor cores are configured to performmatrix operations. In at least one embodiment, one or more tensor coresare included in processing cores 3010. In at least one embodiment,tensor cores are configured to perform deep learning matrix arithmetic,such as convolution operations for neural network training andinferencing. In at least one embodiment, each tensor core operates on a4×4 matrix and performs a matrix multiply and accumulate operationD=A×B+C, where A, B, C, and D are 4×4 matrices.

In at least one embodiment, matrix multiply inputs A and B are 16-bitfloating point matrices and accumulation matrices C and D are 16-bitfloating point or 32-bit floating point matrices. In at least oneembodiment, tensor cores operate on 16-bit floating point input datawith 32-bit floating point accumulation. In at least one embodiment,16-bit floating point multiply uses 64 operations and results in a fullprecision product that is then accumulated using 32-bit floating pointa30ition with other intermediate products for a 4×4×4 matrix multiply.Tensor cores are used to perform much larger two-dimensional or higherdimensional matrix operations, built up from these smaller elements, inat least one embodiment. In at least one embodiment, an API, such as aCUDA-C++ API, exposes specialized matrix load, matrix multiply andaccumulate, and matrix store operations to efficiently use tensor coresfrom a CUDA-C++ program. In at least one embodiment, at the CUDA level,a warp-level interface assumes 16×16 size matrices spanning all 32threads of a warp.

In at least one embodiment, each SM 3000 comprises, without limitation,M SFUs 3012 that perform special functions (e.g., attribute evaluation,reciprocal square root, and like). In at least one embodiment, SFUs 3012include, without limitation, a tree traversal unit configured totraverse a hierarchical tree data structure. In at least one embodiment,SFUs 3012 include, without limitation, a texture unit configured toperform texture map filtering operations. In at least one embodiment,texture units are configured to load texture maps (e.g., a 2D array oftexels) from memory and sample texture maps to produce sampled texturevalues for use in shader programs executed by SM 3000. In at least oneembodiment, texture maps are stored in shared memory/L1 cache 3018. Inat least one embodiment, texture units implement texture operations suchas filtering operations using mip-maps (e.g., texture maps of varyinglevels of detail). In at least one embodiment, each SM 3000 includes,without limitation, two texture units.

In at least one embodiment, each SM 3000 comprises, without limitation,N LSUs 3014 that implement load and store operations between sharedmemory/L1 cache 3018 and register file 3008. In at least one embodiment,each SM 3000 includes, without limitation, interconnect network 3016that connects each of the functional units to register file 3008 and LSU3014 to register file 3008 and shared memory/L1 cache 3018. In at leastone embodiment, interconnect network 3016 is a crossbar that can beconfigured to connect any of the functional units to any of theregisters in register file 3008 and connect LSUs 3014 to register file3008 and memory locations in shared memory/L1 cache 3018.

In at least one embodiment, shared memory/L1 cache 3018 is an array ofon-chip memory that allows for data storage and communication between SM3000 and a primitive engine and between threads in SM 3000. In at leastone embodiment, shared memory/L1 cache 3018 comprises, withoutlimitation, 128 KB of storage capacity and is in a path from SM 3000 toa partition unit. In at least one embodiment, shared memory/L1 cache3018 is used to cache reads and writes. In at least one embodiment, oneor more of shared memory/L1 cache 3018, L2 cache, and memory are backingstores.

In at least one embodiment, combining data cache and shared memoryfunctionality into a single memory block provides improved performancefor both types of memory accesses. In at least one embodiment, capacityis used or is usable as a cache by programs that do not use sharedmemory, such as if shared memory is configured to use half of capacity,texture and load/store operations can use remaining capacity. In atleast one embodiment, integration within shared memory/L1 cache 3018enables shared memory/L1 cache 3018 to function as a high-throughputconduit for streaming data while simultaneously providing high-bandwidthand low-latency access to frequently reused data. In at least oneembodiment, when configured for general purpose parallel computation, asimpler configuration can be used compared with graphics processing. Inat least one embodiment, fixed function GPUs are bypassed, creating amuch simpler programming model. In at least one embodiment and in ageneral purpose parallel computation configuration, a work distributionunit assigns and distributes blocks of threads directly to DPCs. In atleast one embodiment, threads in a block execute the same program, usinga unique thread ID in a calculation to ensure each thread generatesunique results, using SM 3000 to execute a program and performcalculations, shared memory/L1 cache 3018 to communicate betweenthreads, and LSU 3014 to read and write global memory through sharedmemory/L1 cache 3018 and a memory partition unit. In at least oneembodiment, when configured for general purpose parallel computation, SM3000 writes commands that scheduler unit 3004 can use to launch new workon DPCs.

In at least one embodiment, PPU is included in or coupled to a desktopcomputer, a laptop computer, a tablet computer, servers, supercomputers,a smart-phone (e.g., a wireless, hand-held device), a PDA, a digitalcamera, a vehicle, a head mounted display, a hand-held electronicdevice, and more. In at least one embodiment, PPU is embodied on asingle semiconductor substrate. In at least one embodiment, PPU isincluded in an SoC along with one or more other devices such asadditional PPUs, memory, a RISC CPU, an MMU, a digital-to-analogconverter (“DAC”), and like.

In at least one embodiment, PPU may be included on a graphics card thatincludes one or more memory devices. In at least one embodiment, agraphics card may be configured to interface with a PCIe slot on amotherboard of a desktop computer. In at least one embodiment, PPU maybe an integrated GPU (“iGPU”) included in chipset of motherboard.

Software Constructions for General-Purpose Computing

The following FIGS. set forth, without limitation, exemplary softwareconstructs for implementing at least one embodiment.

FIG. 31 illustrates a software stack of a programming platform, inaccordance with at least one embodiment. In at least one embodiment, aprogramming platform is a platform for leveraging hardware on acomputing system to accelerate computational tasks. A programmingplatform may be accessible to software developers through libraries,compiler directives, and/or extensions to programming languages, in atleast one embodiment. In at least one embodiment, a programming platformmay be, but is not limited to, CUDA, Radeon Open Compute Platform(“ROCm”), OpenCL (OpenCL™ is developed by Khronos group), SYCL, or IntelOne API.

In at least one embodiment, a software stack 3100 of a programmingplatform provides an execution environment for an application 3101. Inat least one embodiment, application 3101 may include any computersoftware capable of being launched on software stack 3100. In at leastone embodiment, application 3101 may include, but is not limited to, anartificial intelligence (“AI”)/machine learning (“ML”) application, ahigh performance computing (“HPC”) application, a virtual desktopinfrastructure (“VDI”), or a data center workload.

In at least one embodiment, application 3101 and software stack 3100 runon hardware 3107. Hardware 3107 may include one or more GPUs, CPUs,FPGAs, AI engines, and/or other types of compute devices that support aprogramming platform, in at least one embodiment. In at least oneembodiment, such as with CUDA, software stack 3100 may be vendorspecific and compatible with only devices from particular vendor(s). Inat least one embodiment, such as in with OpenCL, software stack 3100 maybe used with devices from different vendors. In at least one embodiment,hardware 3107 includes a host connected to one more devices that can beaccessed to perform computational tasks via application programminginterface (“API”) calls. A device within hardware 3107 may include, butis not limited to, a GPU, FPGA, AI engine, or other compute device (butmay also include a CPU) and its memory, as opposed to a host withinhardware 3107 that may include, but is not limited to, a CPU (but mayalso include a compute device) and its memory, in at least oneembodiment.

In at least one embodiment, software stack 3100 of a programmingplatform includes, without limitation, a number of libraries 3103, aruntime 3105, and a device kernel driver 3106. Each of libraries 3103may include data and programming code that can be used by computerprograms and leveraged during software development, in at least oneembodiment. In at least one embodiment, libraries 3103 may include, butare not limited to, pre-written code and subroutines, classes, values,type specifications, configuration data, documentation, help data,and/or message templates. In at least one embodiment, libraries 3103include functions that are optimized for execution on one or more typesof devices. In at least one embodiment, libraries 3103 may include, butare not limited to, functions for performing mathematical, deeplearning, and/or other types of operations on devices. In at least oneembodiment, libraries 3103 are associated with corresponding APIs 3102,which may include one or more APIs, that expose functions implemented inlibraries 3103.

In at least one embodiment, application 3101 is written as source codethat is compiled into executable code, as discussed in greater detailbelow in conjunction with FIGS. 36-38 . Executable code of application3101 may run, at least in part, on an execution environment provided bysoftware stack 3100, in at least one embodiment. In at least oneembodiment, during execution of application 3101, code may be reachedthat needs to run on a device, as opposed to a host. In such a case,runtime 3105 may be called to load and launch requisite code on thedevice, in at least one embodiment. In at least one embodiment, runtime3105 may include any technically feasible runtime system that is able tosupport execution of application S01.

In at least one embodiment, runtime 3105 is implemented as one or moreruntime libraries associated with corresponding APIs, which are shown asAPI(s) 3104. One or more of such runtime libraries may include, withoutlimitation, functions for memory management, execution control, devicemanagement, error handling, and/or synchronization, among other things,in at least one embodiment. In at least one embodiment, memorymanagement functions may include, but are not limited to, functions toallocate, deallocate, and copy device memory, as well as transfer databetween host memory and device memory. In at least one embodiment,execution control functions may include, but are not limited to,functions to launch a function (sometimes referred to as a “kernel” whena function is a global function callable from a host) on a device andset attribute values in a buffer maintained by a runtime library for agiven function to be executed on a device.

Runtime libraries and corresponding API(s) 3104 may be implemented inany technically feasible manner, in at least one embodiment. In at leastone embodiment, one (or any number of) API may expose a low-level set offunctions for fine-grained control of a device, while another (or anynumber of) API may expose a higher-level set of such functions. In atleast one embodiment, a high-level runtime API may be built on top of alow-level API. In at least one embodiment, one or more of runtime APIsmay be language-specific APIs that are layered on top of alanguage-independent runtime API.

In at least one embodiment, device kernel driver 3106 is configured tofacilitate communication with an underlying device. In at least oneembodiment, device kernel driver 3106 may provide low-levelfunctionalities upon which APIs, such as API(s) 3104, and/or othersoftware relies. In at least one embodiment, device kernel driver 3106may be configured to compile intermediate representation (“IR”) codeinto binary code at runtime. For CUDA, device kernel driver 3106 maycompile Parallel Thread Execution (“PTX”) IR code that is not hardwarespecific into binary code for a specific target device at runtime (withcaching of compiled binary code), which is also sometimes referred to as“finalizing” code, in at least one embodiment. Doing so may permitfinalized code to run on a target device, which may not have existedwhen source code was originally compiled into PTX code, in at least oneembodiment. Alternatively, in at least one embodiment, device sourcecode may be compiled into binary code offline, without requiring devicekernel driver 3106 to compile IR code at runtime.

FIG. 32 illustrates a CUDA implementation of software stack 3100 of FIG.31 , in accordance with at least one embodiment. In at least oneembodiment, a CUDA software stack 3200, on which an application 3201 maybe launched, includes CUDA libraries 3203, a CUDA runtime 3205, a CUDAdriver 3207, and a device kernel driver 3208. In at least oneembodiment, CUDA software stack 3200 executes on hardware 3209, whichmay include a GPU that supports CUDA and is developed by NVIDIACorporation of Santa Clara, Calif.

In at least one embodiment, application 3201, CUDA runtime 3205, anddevice kernel driver 3208 may perform similar functionalities asapplication 3101, runtime 3105, and device kernel driver 3106,respectively, which are described above in conjunction with FIG. 31 . Inat least one embodiment, CUDA driver 3207 includes a library(libcuda.so) that implements a CUDA driver API 3206. Similar to a CUDAruntime API 3204 implemented by a CUDA runtime library (cudart), CUDAdriver API 3206 may, without limitation, expose functions for memorymanagement, execution control, device management, error handling,synchronization, and/or graphics interoperability, among other things,in at least one embodiment. In at least one embodiment, CUDA driver API3206 differs from CUDA runtime API 3204 in that CUDA runtime API 3204simplifies device code management by providing implicit initialization,context (analogous to a process) management, and module (analogous todynamically loaded libraries) management. In contrast to high-level CUDAruntime API 3204, CUDA driver API 3206 is a low-level API providing morefine-grained control of the device, particularly with respect tocontexts and module loading, in at least one embodiment. In at least oneembodiment, CUDA driver API 3206 may expose functions for contextmanagement that are not exposed by CUDA runtime API 3204. In at leastone embodiment, CUDA driver API 3206 is also language-independent andsupports, e.g., OpenCL in addition to CUDA runtime API 3204. Further, inat least one embodiment, development libraries, including CUDA runtime3205, may be considered as separate from driver components, includinguser-mode CUDA driver 3207 and kernel-mode device driver 3208 (alsosometimes referred to as a “display” driver).

In at least one embodiment, CUDA libraries 3203 may include, but are notlimited to, mathematical libraries, deep learning libraries, parallelalgorithm libraries, and/or signal/image/video processing libraries,which parallel computing applications such as application 3201 mayutilize. In at least one embodiment, CUDA libraries 3203 may includemathematical libraries such as a cuBLAS library that is animplementation of Basic Linear Algebra Subprograms (“BLAS”) forperforming linear algebra operations, a cuFFT library for computing fastFourier transforms (“FFTs”), and a cuRAND library for generating randomnumbers, among others. In at least one embodiment, CUDA libraries 3203may include deep learning libraries such as a cuDNN library ofprimitives for deep neural networks and a TensorRT platform forhigh-performance deep learning inference, among others.

FIG. 33 illustrates a ROCm implementation of software stack 3100 of FIG.31 , in accordance with at least one embodiment. In at least oneembodiment, a ROCm software stack 3300, on which an application 3301 maybe launched, includes a language runtime 3303, a system runtime 3305, athunk 3307, and a ROCm kernel driver 3308. In at least one embodiment,ROCm software stack 3300 executes on hardware 3309, which may include aGPU that supports ROCm and is developed by AMD Corporation of SantaClara, Calif.

In at least one embodiment, application 3301 may perform similarfunctionalities as application 3101 discussed above in conjunction withFIG. 31 . In addition, language runtime 3303 and system runtime 3305 mayperform similar functionalities as runtime 3105 discussed above inconjunction with FIG. 31 , in at least one embodiment. In at least oneembodiment, language runtime 3303 and system runtime 3305 differ in thatsystem runtime 3305 is a language-independent runtime that implements aROCr system runtime API 3304 and makes use of a Heterogeneous SystemArchitecture (“HSA”) Runtime API. HSA runtime API is a thin, user-modeAPI that exposes interfaces to access and interact with an AMD GPU,including functions for memory management, execution control viaarchitected dispatch of kernels, error handling, system and agentinformation, and runtime initialization and shutdown, among otherthings, in at least one embodiment. In contrast to system runtime 3305,language runtime 3303 is an implementation of a language-specificruntime API 3302 layered on top of ROCr system runtime API 3304, in atleast one embodiment. In at least one embodiment, language runtime APImay include, but is not limited to, a Heterogeneous compute Interfacefor Portability (“HIP”) language runtime API, a Heterogeneous ComputeCompiler (“HCC”) language runtime API, or an OpenCL API, among others.HIP language in particular is an extension of C++ programming languagewith functionally similar versions of CUDA mechanisms, and, in at leastone embodiment, a HIP language runtime API includes functions that aresimilar to those of CUDA runtime API 3204 discussed above in conjunctionwith FIG. 32 , such as functions for memory management, executioncontrol, device management, error handling, and synchronization, amongother things.

In at least one embodiment, thunk (ROCt) 3307 is an interface 3306 thatcan be used to interact with underlying ROCm driver 3308. In at leastone embodiment, ROCm driver 3308 is a ROCk driver, which is acombination of an AMDGPU driver and a HSA kernel driver (amdkfd). In atleast one embodiment, AMDGPU driver is a device kernel driver for GPUsdeveloped by AMD that performs similar functionalities as device kerneldriver 3106 discussed above in conjunction with FIG. 31 . In at leastone embodiment, HSA kernel driver is a driver permitting different typesof processors to share system resources more effectively via hardwarefeatures.

In at least one embodiment, various libraries (not shown) may beincluded in ROCm software stack 3300 above language runtime 3303 andprovide functionality similarity to CUDA libraries 3203, discussed abovein conjunction with FIG. 32 . In at least one embodiment, variouslibraries may include, but are not limited to, mathematical, deeplearning, and/or other libraries such as a hipBLAS library thatimplements functions similar to those of CUDA cuBLAS, a rocFFT libraryfor computing FFTs that is similar to CUDA cuFFT, among others.

FIG. 34 illustrates an OpenCL implementation of software stack 3100 ofFIG. 31 , in accordance with at least one embodiment. In at least oneembodiment, an OpenCL software stack 3400, on which an application 3401may be launched, includes an OpenCL framework 3410, an OpenCL runtime3406, and a driver 3407. In at least one embodiment, OpenCL softwarestack 3400 executes on hardware 3209 that is not vendor-specific. AsOpenCL is supported by devices developed by different vendors, specificOpenCL drivers may be required to interoperate with hardware from suchvendors, in at least one embodiment.

In at least one embodiment, application 3401, OpenCL runtime 3406,device kernel driver 3407, and hardware 3408 may perform similarfunctionalities as application 3101, runtime 3105, device kernel driver3106, and hardware 3107, respectively, that are discussed above inconjunction with FIG. 31 . In at least one embodiment, application 3401further includes an OpenCL kernel 3402 with code that is to be executedon a device.

In at least one embodiment, OpenCL defines a “platform” that allows ahost to control devices connected to the host. In at least oneembodiment, an OpenCL framework provides a platform layer API and aruntime API, shown as platform API 3403 and runtime API 3405. In atleast one embodiment, runtime API 3405 uses contexts to manage executionof kernels on devices. In at least one embodiment, each identifieddevice may be associated with a respective context, which runtime API3405 may use to manage command queues, program objects, and kernelobjects, share memory objects, among other things, for that device. Inat least one embodiment, platform API 3403 exposes functions that permitdevice contexts to be used to select and initialize devices, submit workto devices via command queues, and enable data transfer to and fromdevices, among other things. In addition, OpenCL framework providesvarious built-in functions (not shown), including math functions,relational functions, and image processing functions, among others, inat least one embodiment.

In at least one embodiment, a compiler 3404 is also included in OpenCLframe-work 3410. Source code may be compiled offline prior to executingan application or online during execution of an application, in at leastone embodiment. In contrast to CUDA and ROCm, OpenCL applications in atleast one embodiment may be compiled online by compiler 3404, which isincluded to be representative of any number of compilers that may beused to compile source code and/or IR code, such as Standard PortableIntermediate Representation (“SPIR-V”) code, into binary code.Alternatively, in at least one embodiment, OpenCL ap-plications may becompiled offline, prior to execution of such applications.

FIG. 35 illustrates software that is supported by a programmingplatform, in accordance with at least one embodiment. In at least oneembodiment, a programming platform 3504 is configured to support variousprogramming models 3503, middlewares and/or libraries 3502, andframeworks 3501 that an application 3500 may rely upon. In at least oneembodiment, application 3500 may be an AI/ML application implementedusing, for example, a deep learning framework such as MXNet, PyTorch, orTensorFlow, which may rely on libraries such as cuDNN, NVIDIA CollectiveCommunications Library (“NCCL”), and/or NVIDA Developer Data LoadingLibrary (“DALI”) CUDA libraries to provide accelerated computing onunderlying hardware.

In at least one embodiment, programming platform 3504 may be one of aCUDA, ROCm, or OpenCL platform described above in conjunction with FIG.32 , FIG. 33 , and FIG. 34 , respectively. In at least one embodiment,programming platform 3504 supports multiple programming models 3503,which are abstractions of an underlying computing system permittingexpressions of algorithms and data structures. Programming models 3503may expose features of underlying hardware in order to improveperformance, in at least one embodiment. In at least one embodiment,programming models 3503 may include, but are not limited to, CUDA, HIP,OpenCL, C++ Accelerated Massive Parallelism (“C++ AMP”), OpenMulti-Processing (“OpenMP”), Open Accelerators (“OpenACC”), and/orVulcan Compute.

In at least one embodiment, libraries and/or middlewares 3502 provideimplementations of abstractions of programming models 3504. In at leastone embodiment, such libraries include data and programming code thatmay be used by computer programs and leveraged during softwaredevelopment. In at least one embodiment, such middlewares includesoftware that provides services to applications beyond those availablefrom programming platform 3504. In at least one embodiment, librariesand/or middlewares 3502 may include, but are not limited to, cuBLAS,cuFFT, cuRAND, and other CUDA libraries, or rocBLAS, rocFFT, rocRAND,and other ROCm libraries. In addition, in at least one embodiment,libraries and/or middlewares 3502 may include NCCL and ROCmCommunication Collectives Library (“RCCL”) libraries providingcommunication routines for GPUs, a MIOpen library for deep learningacceleration, and/or an Eigen library for linear algebra, matrix andvector operations, geometrical transformations, numerical solvers, andrelated algorithms.

In at least one embodiment, application frameworks 3501 depend onlibraries and/or middlewares 3502. In at least one embodiment, each ofapplication frameworks 3501 is a software framework used to implement astandard structure of application software. Returning to the AI/MLexample discussed above, an AI/ML application may be implemented using aframework such as Caffe, Caffe2, TensorFlow, Keras, PyTorch, or MxNetdeep learning frameworks, in at least one embodiment.

FIG. 36 illustrates compiling code to execute on one of programmingplatforms of FIGS. 31-34 , in accordance with at least one embodiment.In at least one embodiment, a compiler 3601 receives source code 3600that includes both host code as well as device code. In at least oneembodiment, complier 3601 is configured to convert source code 3600 intohost executable code 3602 for execution on a host and device executablecode 3603 for execution on a device. In at least one embodiment, sourcecode 3600 may either be compiled offline prior to execution of anapplication, or online during execution of an application.

In at least one embodiment, source code 3600 may include code in anyprogramming language supported by compiler 3601, such as C++, C,Fortran, etc. In at least one embodiment, source code 3600 may beincluded in a single-source file having a mixture of host code anddevice code, with locations of device code being indicated therein. Inat least one embodiment, a single-source file may be a .cu file thatincludes CUDA code or a .hip.cpp file that includes HIP code.Alternatively, in at least one embodiment, source code 3600 may includemultiple source code files, rather than a single-source file, into whichhost code and device code are separated.

In at least one embodiment, compiler 3601 is configured to compilesource code 3600 into host executable code 3602 for execution on a hostand device executable code 3603 for execution on a device. In at leastone embodiment, compiler 3601 performs operations including parsingsource code 3600 into an abstract system tree (AST), performingoptimizations, and generating executable code. In at least oneembodiment in which source code 3600 includes a single-source file,compiler 3601 may separate device code from host code in such asingle-source file, compile device code and host code into deviceexecutable code 3603 and host executable code 3602, respectively, andlink device executable code 3603 and host executable code 3602 togetherin a single file, as discussed in greater detail below with respect toFIG. 37 .

In at least one embodiment, host executable code 3602 and deviceexecutable code 3603 may be in any suitable format, such as binary codeand/or IR code. In the case of CUDA, host executable code 3602 mayinclude native object code and device executable code 3603 may includecode in PTX intermediate representation, in at least one embodiment. Inthe case of ROCm, both host executable code 3602 and device executablecode 3603 may include target binary code, in at least one embodiment.

FIG. 37 is a more detailed illustration of compiling code to execute onone of programming platforms of FIGS. 31-34 , in accordance with atleast one embodiment. In at least one embodiment, a compiler 3701 isconfigured to receive source code 3700, compile source code 3700, andoutput an executable file 3710. In at least one embodiment, source code3700 is a single-source file, such as a .cu file, a .hip.cpp file, or afile in another format, that includes both host and device code. In atleast one embodiment, compiler 3701 may be, but is not limited to, anNVIDIA CUDA compiler (“NVCC”) for compiling CUDA code in .cu files, or aHCC compiler for compiling HIP code in .hip.cpp files.

In at least one embodiment, compiler 3701 includes a compiler front end3702, a host compiler 3705, a device compiler 3706, and a linker 3709.In at least one embodiment, compiler front end 3702 is configured toseparate device code 3704 from host code 3703 in source code 3700.Device code 3704 is compiled by device compiler 3706 into deviceexecutable code 3708, which as described may include binary code or IRcode, in at least one embodiment. Separately, host code 3703 is compiledby host compiler 3705 into host executable code 3707, in at least oneembodiment. For NVCC, host compiler 3705 may be, but is not limited to,a general purpose C/C++ compiler that outputs native object code, whiledevice compiler 3706 may be, but is not limited to, a Low Level VirtualMachine (“LLVM”)-based compiler that forks a LLVM compilerinfrastructure and outputs PTX code or binary code, in at least oneembodiment. For HCC, both host compiler 3705 and device compiler 3706may be, but are not limited to, LLVM-based compilers that output targetbinary code, in at least one embodiment.

Subsequent to compiling source code 3700 into host executable code 3707and device executable code 3708, linker 3709 links host and deviceexecutable code 3707 and 3708 together in executable file 3710, in atleast one embodiment. In at least one embodiment, native object code fora host and PTX or binary code for a device may be linked together in anExecutable and Linkable Format (“ELF”) file, which is a container formatused to store object code.

FIG. 38 illustrates translating source code prior to compiling sourcecode, in accordance with at least one embodiment. In at least oneembodiment, source code 3800 is passed through a translation tool 3801,which translates source code 3800 into translated source code 3802. Inat least one embodiment, a compiler 3803 is used to compile translatedsource code 3802 into host executable code 3804 and device executablecode 3805 in a process that is similar to compilation of source code3600 by compiler 3601 into host executable code 3602 and deviceexecutable 3603, as discussed above in conjunction with FIG. 36 .

In at least one embodiment, a translation performed by translation tool3801 is used to port source 3800 for execution in a differentenvironment than that in which it was originally intended to run. In atleast one embodiment, translation tool 3801 may include, but is notlimited to, a HIP translator that is used to “hipify” CUDA code intendedfor a CUDA platform into HIP code that can be compiled and executed on aROCm platform. In at least one embodiment, translation of source code3800 may include parsing source code 3800 and converting calls to API(s)provided by one programming model (e.g., CUDA) into corresponding callsto API(s) provided by another programming model (e.g., HIP), asdiscussed in greater detail below in conjunction with FIGS. 39A-40 .Returning to the example of hipifying CUDA code, calls to CUDA runtimeAPI, CUDA driver API, and/or CUDA libraries may be converted tocorresponding HIP API calls, in at least one embodiment. In at least oneembodiment, automated translations performed by translation tool 3801may sometimes be incomplete, requiring additional, manual effort tofully port source code 3800.

Configuring GPUs for General-Purpose Computing

The following FIGS. set forth, without limitation, exemplaryarchitectures for compiling and executing compute source code, inaccordance with at least one embodiment.

FIG. 39A illustrates a system 3900 configured to compile and executeCUDA source code 3910 using different types of processing units, inaccordance with at least one embodiment. In at least one embodiment,system 3900 includes, without limitation, CUDA source code 3910, a CUDAcompiler 3950, host executable code 3970(1), host executable code3970(2), CUDA device executable code 3984, a CPU 3990, a CUDA-enabledGPU 3994, a GPU 3992, a CUDA to HIP translation tool 3920, HIP sourcecode 3930, a HIP compiler driver 3940, an HCC 3960, and HCC deviceexecutable code 3982.

In at least one embodiment, CUDA source code 3910 is a collection ofhuman-readable code in a CUDA programming language. In at least oneembodiment, CUDA code is human-readable code in a CUDA programminglanguage. In at least one embodiment, a CUDA programming language is anextension of the C++ programming language that includes, withoutlimitation, mechanisms to define device code and distinguish betweendevice code and host code. In at least one embodiment, device code issource code that, after compilation, is executable in parallel on adevice. In at least one embodiment, a device may be a processor that isoptimized for parallel instruction processing, such as CUDA-enabled GPU3990, GPU 39192, or another GPGPU, etc. In at least one embodiment, hostcode is source code that, after compilation, is executable on a host. Inat least one embodiment, a host is a processor that is optimized forsequential instruction processing, such as CPU 3990.

In at least one embodiment, CUDA source code 3910 includes, withoutlimitation, any number (including zero) of global functions 3912, anynumber (including zero) of device functions 3914, any number (includingzero) of host functions 3916, and any number (including zero) ofhost/device functions 3918. In at least one embodiment, global functions3912, device functions 3914, host functions 3916, and host/devicefunctions 3918 may be mixed in CUDA source code 3910. In at least oneembodiment, each of global functions 3912 is executable on a device andcallable from a host. In at least one embodiment, one or more of globalfunctions 3912 may therefore act as entry points to a device. In atleast one embodiment, each of global functions 3912 is a kernel. In atleast one embodiment and in a technique known as dynamic parallelism,one or more of global functions 3912 defines a kernel that is executableon a device and callable from such a device. In at least one embodiment,a kernel is executed N (where N is any positive integer) times inparallel by N different threads on a device during execution.

In at least one embodiment, each of device functions 3914 is executed ona device and callable from such a device only. In at least oneembodiment, each of host functions 3916 is executed on a host andcallable from such a host only. In at least one embodiment, each ofhost/device functions 3916 defines both a host version of a functionthat is executable on a host and callable from such a host only and adevice version of the function that is executable on a device andcallable from such a device only.

In at least one embodiment, CUDA source code 3910 may also include,without limitation, any number of calls to any number of functions thatare defined via a CUDA runtime API 3902. In at least one embodiment,CUDA runtime API 3902 may include, without limitation, any number offunctions that execute on a host to allocate and deallocate devicememory, transfer data between host memory and device memory, managesystems with multiple devices, etc. In at least one embodiment, CUDAsource code 3910 may also include any number of calls to any number offunctions that are specified in any number of other CUDA APIs. In atleast one embodiment, a CUDA API may be any API that is designed for useby CUDA code. In at least one embodiment, CUDA APIs include, withoutlimitation, CUDA runtime API 3902, a CUDA driver API, APIs for anynumber of CUDA libraries, etc. In at least one embodiment and relativeto CUDA runtime API 3902, a CUDA driver API is a lower-level API butprovides finer-grained control of a device. In at least one embodiment,examples of CUDA libraries include, without limitation, cuBLAS, cuFFT,cuRAND, cuDNN, etc.

In at least one embodiment, CUDA compiler 3950 compiles input CUDA code(e.g., CUDA source code 3910) to generate host executable code 3970(1)and CUDA device executable code 3984. In at least one embodiment, CUDAcompiler 3950 is NVCC. In at least one embodiment, host executable code3970(1) is a compiled version of host code included in input source codethat is executable on CPU 3990. In at least one embodiment, CPU 3990 maybe any processor that is optimized for sequential instructionprocessing.

In at least one embodiment, CUDA device executable code 3984 is acompiled version of device code included in input source code that isexecutable on CUDA-enabled GPU 3994. In at least one embodiment, CUDAdevice executable code 3984 includes, without limitation, binary code.In at least one embodiment, CUDA device executable code 3984 includes,without limitation, IR code, such as PTX code, that is further compiledat runtime into binary code for a specific target device (e.g.,CUDA-enabled GPU 3994) by a device driver. In at least one embodiment,CUDA-enabled GPU 3994 may be any processor that is optimized forparallel instruction processing and that supports CUDA. In at least oneembodiment, CUDA-enabled GPU 3994 is developed by NVIDIA Corporation ofSanta Clara, Calif.

In at least one embodiment, CUDA to HIP translation tool 3920 isconfigured to translate CUDA source code 3910 to functionally similarHIP source code 3930. In a least one embodiment, HIP source code 3930 isa collection of human-readable code in a HIP programming language. In atleast one embodiment, HIP code is human-readable code in a HIPprogramming language. In at least one embodiment, a HIP programminglanguage is an extension of the C++ programming language that includes,without limitation, functionally similar versions of CUDA mechanisms todefine device code and distinguish between device code and host code. Inat least one embodiment, a HIP programming language may include a subsetof functionality of a CUDA programming language. In at least oneembodiment, for example, a HIP programming language includes, withoutlimitation, mechanism(s) to define global functions 3912, but such a HIPprogramming language may lack support for dynamic parallelism andtherefore global functions 3912 defined in HIP code may be callable froma host only.

In at least one embodiment, HIP source code 3930 includes, withoutlimitation, any number (including zero) of global functions 3912, anynumber (including zero) of device functions 3914, any number (includingzero) of host functions 3916, and any number (including zero) ofhost/device functions 3918. In at least one embodiment, HIP source code3930 may also include any number of calls to any number of functionsthat are specified in a HIP runtime API 3932. In at least oneembodiment, HIP runtime API 3932 includes, without limitation,functionally similar versions of a subset of functions included in CUDAruntime API 3902. In at least one embodiment, HIP source code 3930 mayalso include any number of calls to any number of functions that arespecified in any number of other HIP APIs. In at least one embodiment, aHIP API may be any API that is designed for use by HIP code and/or ROCm.In at least one embodiment, HIP APIs include, without limitation, HIPruntime API 3932, a HIP driver API, APIs for any number of HIPlibraries, APIs for any number of ROCm libraries, etc.

In at least one embodiment, CUDA to HIP translation tool 3920 convertseach kernel call in CUDA code from a CUDA syntax to a HIP syntax andconverts any number of other CUDA calls in CUDA code to any number ofother functionally similar HIP calls. In at least one embodiment, a CUDAcall is a call to a function specified in a CUDA API, and a HIP call isa call to a function specified in a HIP API. In at least one embodiment,CUDA to HIP translation tool 3920 converts any number of calls tofunctions specified in CUDA runtime API 3902 to any number of calls tofunctions specified in HIP runtime API 3932.

In at least one embodiment, CUDA to HIP translation tool 3920 is a toolknown as hipify-perl that executes a text-based translation process. Inat least one embodiment, CUDA to HIP translation tool 3920 is a toolknown as hipify-clang that, relative to hipify-perl, executes a morecomplex and more robust translation process that involves parsing CUDAcode using clang (a compiler front-end) and then translating resultingsymbols. In at least one embodiment, properly converting CUDA code toHIP code may require modifications (e.g., manual edits) in addition tothose performed by CUDA to HIP translation tool 3920.

In at least one embodiment, HIP compiler driver 3940 is a front end thatdetermines a target device 3946 and then configures a compiler that iscompatible with target device 3946 to compile HIP source code 3930. Inat least one embodiment, target device 3946 is a processor that isoptimized for parallel instruction processing. In at least oneembodiment, HIP compiler driver 3940 may determine target device 3946 inany technically feasible fashion.

In at least one embodiment, if target device 3946 is compatible withCUDA (e.g., CUDA-enabled GPU 3994), then HIP compiler driver 3940generates a HIP/NVCC compilation command 3942. In at least oneembodiment and as described in greater detail in conjunction with FIG.39B, HIP/NVCC compilation command 3942 configures CUDA compiler 3950 tocompile HIP source code 3930 using, without limitation, a HIP to CUDAtranslation header and a CUDA runtime library. In at least oneembodiment and in response to HIP/NVCC compilation command 3942, CUDAcompiler 3950 generates host executable code 3970(1) and CUDA deviceexecutable code 3984.

In at least one embodiment, if target device 3946 is not compatible withCUDA, then HIP compiler driver 3940 generates a HIP/HCC compilationcommand 3944. In at least one embodiment and as described in greaterdetail in conjunction with FIG. 39C, HIP/HCC compilation command 3944configures HCC 3960 to compile HIP source code 3930 using, withoutlimitation, an HCC header and a HIP/HCC runtime library. In at least oneembodiment and in response to HIP/HCC compilation command 3944, HCC 3960generates host executable code 3970(2) and HCC device executable code3982. In at least one embodiment, HCC device executable code 3982 is acompiled version of device code included in HIP source code 3930 that isexecutable on GPU 3992. In at least one embodiment, GPU 3992 may be anyprocessor that is optimized for parallel instruction processing, is notcompatible with CUDA, and is compatible with HCC. In at least oneembodiment, GPU 3992 is developed by AMD Corporation of Santa Clara,Calif. In at least one embodiment GPU, 3992 is a non-CUDA-enabled GPU3992.

For explanatory purposes only, three different flows that may beimplemented in at least one embodiment to compile CUDA source code 3910for execution on CPU 3990 and different devices are depicted in FIG.39A. In at least one embodiment, a direct CUDA flow compiles CUDA sourcecode 3910 for execution on CPU 3990 and CUDA-enabled GPU 3994 withouttranslating CUDA source code 3910 to HIP source code 3930. In at leastone embodiment, an indirect CUDA flow translates CUDA source code 3910to HIP source code 3930 and then compiles HIP source code 3930 forexecution on CPU 3990 and CUDA-enabled GPU 3994. In at least oneembodiment, a CUDA/HCC flow translates CUDA source code 3910 to HIPsource code 3930 and then compiles HIP source code 3930 for execution onCPU 3990 and GPU 3992.

A direct CUDA flow that may be implemented in at least one embodiment isdepicted via dashed lines and a series of bubbles annotated A1-A3. In atleast one embodiment and as depicted with bubble annotated A1, CUDAcompiler 3950 receives CUDA source code 3910 and a CUDA compile command3948 that configures CUDA compiler 3950 to compile CUDA source code3910. In at least one embodiment, CUDA source code 3910 used in a directCUDA flow is written in a CUDA programming language that is based on aprogramming language other than C++ (e.g., C, Fortran, Python, Java,etc.). In at least one embodiment and in response to CUDA compilecommand 3948, CUDA compiler 3950 generates host executable code 3970(1)and CUDA device executable code 3984 (depicted with bubble annotatedA2). In at least one embodiment and as depicted with bubble annotatedA3, host executable code 3970(1) and CUDA device executable code 3984may be executed on, respectively, CPU 3990 and CUDA-enabled GPU 3994. Inat least one embodiment, CUDA device executable code 3984 includes,without limitation, binary code. In at least one embodiment, CUDA deviceexecutable code 3984 includes, without limitation, PTX code and isfurther compiled into binary code for a specific target device atruntime.

An indirect CUDA flow that may be implemented in at least one embodimentis depicted via dotted lines and a series of bubbles annotated B1-B6. Inat least one embodiment and as depicted with bubble annotated B1, CUDAto HIP translation tool 3920 receives CUDA source code 3910. In at leastone embodiment and as depicted with bubble annotated B2, CUDA to HIPtranslation tool 3920 translates CUDA source code 3910 to HIP sourcecode 3930. In at least one embodiment and as depicted with bubbleannotated B3, HIP compiler driver 3940 receives HIP source code 3930 anddetermines that target device 3946 is CUDA-enabled.

In at least one embodiment and as depicted with bubble annotated B4, HIPcompiler driver 3940 generates HIP/NVCC compilation command 3942 andtransmits both HIP/NVCC compilation command 3942 and HIP source code3930 to CUDA compiler 3950. In at least one embodiment and as describedin greater detail in conjunction with FIG. 39B, HIP/NVCC compilationcommand 3942 configures CUDA compiler 3950 to compile HIP source code3930 using, without limitation, a HIP to CUDA translation header and aCUDA runtime library. In at least one embodiment and in response toHIP/NVCC compilation command 3942, CUDA compiler 3950 generates hostexecutable code 3970(1) and CUDA device executable code 3984 (depictedwith bubble annotated B5). In at least one embodiment and as depictedwith bubble annotated B6, host executable code 3970(1) and CUDA deviceexecutable code 3984 may be executed on, respectively, CPU 3990 andCUDA-enabled GPU 3994. In at least one embodiment, CUDA deviceexecutable code 3984 includes, without limitation, binary code. In atleast one embodiment, CUDA device executable code 3984 includes, withoutlimitation, PTX code and is further compiled into binary code for aspecific target device at runtime.

A CUDA/HCC flow that may be implemented in at least one embodiment isdepicted via solid lines and a series of bubbles annotated C1-C6. In atleast one embodiment and as depicted with bubble annotated C1, CUDA toHIP translation tool 3920 receives CUDA source code 3910. In at leastone embodiment and as depicted with bubble annotated C2, CUDA to HIPtranslation tool 3920 translates CUDA source code 3910 to HIP sourcecode 3930. In at least one embodiment and as depicted with bubbleannotated C3, HIP compiler driver 3940 receives HIP source code 3930 anddetermines that target device 3946 is not CUDA-enabled.

In at least one embodiment, HIP compiler driver 3940 generates HIP/HCCcompilation command 3944 and transmits both HIP/HCC compilation command3944 and HIP source code 3930 to HCC 3960 (depicted with bubbleannotated C4). In at least one embodiment and as described in greaterdetail in conjunction with FIG. 39C, HIP/HCC compilation command 3944configures HCC 3960 to compile HIP source code 3930 using, withoutlimitation, an HCC header and a HIP/HCC runtime library. In at least oneembodiment and in response to HIP/HCC compilation command 3944, HCC 3960generates host executable code 3970(2) and HCC device executable code3982 (depicted with bubble annotated C5). In at least one embodiment andas depicted with bubble annotated C6, host executable code 3970(2) andHCC device executable code 3982 may be executed on, respectively, CPU3990 and GPU 3992.

In at least one embodiment, after CUDA source code 3910 is translated toHIP source code 3930, HIP compiler driver 3940 may subsequently be usedto generate executable code for either CUDA-enabled GPU 3994 or GPU 3992without re-executing CUDA to HIP translation tool 3920. In at least oneembodiment, CUDA to HIP translation tool 3920 translates CUDA sourcecode 3910 to HIP source code 3930 that is then stored in memory. In atleast one embodiment, HIP compiler driver 3940 then configures HCC 3960to generate host executable code 3970(2) and HCC device executable code3982 based on HIP source code 3930. In at least one embodiment, HIPcompiler driver 3940 subsequently configures CUDA compiler 3950 togenerate host executable code 3970(1) and CUDA device executable code3984 based on stored HIP source code 3930.

FIG. 39B illustrates a system 3904 configured to compile and executeCUDA source code 3910 of FIG. 39A using CPU 3990 and CUDA-enabled GPU3994, in accordance with at least one embodiment. In at least oneembodiment, system 3904 includes, without limitation, CUDA source code3910, CUDA to HIP translation tool 3920, HIP source code 3930, HIPcompiler driver 3940, CUDA compiler 3950, host executable code 3970(1),CUDA device executable code 3984, CPU 3990, and CUDA-enabled GPU 3994.

In at least one embodiment and as described previously herein inconjunction with FIG. 39A, CUDA source code 3910 includes, withoutlimitation, any number (including zero) of global functions 3912, anynumber (including zero) of device functions 3914, any number (includingzero) of host functions 3916, and any number (including zero) ofhost/device functions 3918. In at least one embodiment, CUDA source code3910 also includes, without limitation, any number of calls to anynumber of functions that are specified in any number of CUDA APIs.

In at least one embodiment, CUDA to HIP translation tool 3920 translatesCUDA source code 3910 to HIP source code 3930. In at least oneembodiment, CUDA to HIP translation tool 3920 converts each kernel callin CUDA source code 3910 from a CUDA syntax to a HIP syntax and convertsany number of other CUDA calls in CUDA source code 3910 to any number ofother functionally similar HIP calls.

In at least one embodiment, HIP compiler driver 3940 determines thattarget device 3946 is CUDA-enabled and generates HIP/NVCC compilationcommand 3942. In at least one embodiment, HIP compiler driver 3940 thenconfigures CUDA compiler 3950 via HIP/NVCC compilation command 3942 tocompile HIP source code 3930. In at least one embodiment, HIP compilerdriver 3940 provides access to a HIP to CUDA translation header 3952 aspart of configuring CUDA compiler 3950. In at least one embodiment, HIPto CUDA translation header 3952 translates any number of mechanisms(e.g., functions) specified in any number of HIP APIs to any number ofmechanisms specified in any number of CUDA APIs. In at least oneembodiment, CUDA compiler 3950 uses HIP to CUDA translation header 3952in conjunction with a CUDA runtime library 3954 corresponding to CUDAruntime API 3902 to generate host executable code 3970(1) and CUDAdevice executable code 3984. In at least one embodiment, host executablecode 3970(1) and CUDA device executable code 3984 may then be executedon, respectively, CPU 3990 and CUDA-enabled GPU 3994. In at least oneembodiment, CUDA device executable code 3984 includes, withoutlimitation, binary code. In at least one embodiment, CUDA deviceexecutable code 3984 includes, without limitation, PTX code and isfurther compiled into binary code for a specific target device atruntime.

FIG. 39C illustrates a system 3906 configured to compile and executeCUDA source code 3910 of FIG. 39A using CPU 3990 and non-CUDA-enabledGPU 3992, in accordance with at least one embodiment. In at least oneembodiment, system 3906 includes, without limitation, CUDA source code3910, CUDA to HIP translation tool 3920, HIP source code 3930, HIPcompiler driver 3940, HCC 3960, host executable code 3970(2), HCC deviceexecutable code 3982, CPU 3990, and GPU 3992.

In at least one embodiment and as described previously herein inconjunction with FIG. 39A, CUDA source code 3910 includes, withoutlimitation, any number (including zero) of global functions 3912, anynumber (including zero) of device functions 3914, any number (includingzero) of host functions 3916, and any number (including zero) ofhost/device functions 3918. In at least one embodiment, CUDA source code3910 also includes, without limitation, any number of calls to anynumber of functions that are specified in any number of CUDA APIs.

In at least one embodiment, CUDA to HIP translation tool 3920 translatesCUDA source code 3910 to HIP source code 3930. In at least oneembodiment, CUDA to HIP translation tool 3920 converts each kernel callin CUDA source code 3910 from a CUDA syntax to a HIP syntax and convertsany number of other CUDA calls in source code 3910 to any number ofother functionally similar HIP calls.

In at least one embodiment, HIP compiler driver 3940 subsequentlydetermines that target device 3946 is not CUDA-enabled and generatesHIP/HCC compilation command 3944. In at least one embodiment, HIPcompiler driver 3940 then configures HCC 3960 to execute HIP/HCCcompilation command 3944 to compile HIP source code 3930. In at leastone embodiment, HIP/HCC compilation command 3944 configures HCC 3960 touse, without limitation, a HIP/HCC runtime library 3958 and an HCCheader 3956 to generate host executable code 3970(2) and HCC deviceexecutable code 3982. In at least one embodiment, HIP/HCC runtimelibrary 3958 corresponds to HIP runtime API 3932. In at least oneembodiment, HCC header 3956 includes, without limitation, any number andtype of interoperability mechanisms for HIP and HCC. In at least oneembodiment, host executable code 3970(2) and HCC device executable code3982 may be executed on, respectively, CPU 3990 and GPU 3992.

FIG. 40 illustrates an exemplary kernel translated by CUDA-to-HIPtranslation tool 3920 of FIG. 39C, in accordance with at least oneembodiment. In at least one embodiment, CUDA source code 3910 partitionsan overall problem that a given kernel is designed to solve intorelatively coarse sub-problems that can independently be solved usingthread blocks. In at least one embodiment, each thread block includes,without limitation, any number of threads. In at least one embodiment,each sub-problem is partitioned into relatively fine pieces that can besolved cooperatively in parallel by threads within a thread block. In atleast one embodiment, threads within a thread block can cooperate bysharing data through shared memory and by synchronizing execution tocoordinate memory accesses.

In at least one embodiment, CUDA source code 3910 organizes threadblocks associated with a given kernel into a one-dimensional, atwo-dimensional, or a three-dimensional grid of thread blocks. In atleast one embodiment, each thread block includes, without limitation,any number of threads, and a grid includes, without limitation, anynumber of thread blocks.

In at least one embodiment, a kernel is a function in device code thatis defined using a “_global_” declaration specifier. In at least oneembodiment, the dimension of a grid that executes a kernel for a givenkernel call and associated streams are specified using a CUDA kernellaunch syntax 4010. In at least one embodiment, CUDA kernel launchsyntax 4010 is specified as “KernelName<<<GridSize, BlockSize,SharedMemorySize, Stream>>>(KernelArguments);”. In at least oneembodiment, an execution configuration syntax is a “<<< . . . >>>”construct that is inserted between a kernel name (“KernelName”) and aparenthesized list of kernel arguments (“KernelArguments”). In at leastone embodiment, CUDA kernel launch syntax 4010 includes, withoutlimitation, a CUDA launch function syntax instead of an executionconfiguration syntax.

In at least one embodiment, “GridSize” is of a type dim3 and specifiesthe dimension and size of a grid. In at least one embodiment, type dim3is a CUDA-defined structure that includes, without limitation, unsignedintegers x, y, and z. In at least one embodiment, if z is not specified,then z defaults to one. In at least one embodiment, if y is notspecified, then y defaults to one. In at least one embodiment, thenumber of thread blocks in a grid is equal to the product of GridSize.x,GridSize.y, and GridSize.z. In at least one embodiment, “BlockSize” isof type dim3 and specifies the dimension and size of each thread block.In at least one embodiment, the number of threads per thread block isequal to the product of BlockSize.x, BlockSize.y, and BlockSize.z. In atleast one embodiment, each thread that executes a kernel is given aunique thread ID that is accessible within the kernel through a built-invariable (e.g., “threadIdx”).

In at least one embodiment and with respect to CUDA kernel launch syntax4010, “SharedMemorySize” is an optional argument that specifies a numberof bytes in a shared memory that is dynamically allocated per threadblock for a given kernel call in addition to statically allocatedmemory. In at least one embodiment and with respect to CUDA kernellaunch syntax 4010, SharedMemorySize defaults to zero. In at least oneembodiment and with respect to CUDA kernel launch syntax 4010, “Stream”is an optional argument that specifies an associated stream and defaultsto zero to specify a default stream. In at least one embodiment, astream is a sequence of commands (possibly issued by different hostthreads) that execute in order. In at least one embodiment, differentstreams may execute commands out of order with respect to one another orconcurrently.

In at least one embodiment, CUDA source code 3910 includes, withoutlimitation, a kernel definition for an exemplary kernel “MatAdd” and amain function. In at least one embodiment, main function is host codethat executes on a host and includes, without limitation, a kernel callthat causes kernel MatAdd to execute on a device. In at least oneembodiment and as shown, kernel MatAdd adds two matrices A and B of sizeN×N, where N is a positive integer, and stores the result in a matrix C.In at least one embodiment, main function defines a threadsPerBlockvariable as 16 by 16 and a numBlocks variable as N/16 by N/16. In atleast one embodiment, main function then specifies kernel call“MatAdd<<<numBlocks, threadsPerBlock>>>(A, B, C);”. In at least oneembodiment and as per CUDA kernel launch syntax 4010, kernel MatAdd isexecuted using a grid of thread blocks having a dimension N/16 by N/16,where each thread block has a dimension of 16 by 16. In at least oneembodiment, each thread block includes 256 threads, a grid is createdwith enough blocks to have one thread per matrix element, and eachthread in such a grid executes kernel MatAdd to perform one pair-wiseaddition.

In at least one embodiment, while translating CUDA source code 3910 toHIP source code 3930, CUDA to HIP translation tool 3920 translates eachkernel call in CUDA source code 3910 from CUDA kernel launch syntax 4010to a HIP kernel launch syntax 4020 and converts any number of other CUDAcalls in source code 3910 to any number of other functionally similarHIP calls. In at least one embodiment, HIP kernel launch syntax 4020 isspecified as “hipLaunchKernelGGL(KernelName, GridSize, BlockSize,SharedMemorySize, Stream, KernelArguments);”. In at least oneembodiment, each of KernelName, GridSize, BlockSize, ShareMemorySize,Stream, and KernelArguments has the same meaning in HIP kernel launchsyntax 4020 as in CUDA kernel launch syntax 4010 (described previouslyherein). In at least one embodiment, arguments SharedMemorySize andStream are required in HIP kernel launch syntax 4020 and are optional inCUDA kernel launch syntax 4010.

In at least one embodiment, a portion of HIP source code 3930 depictedin FIG. 40 is identical to a portion of CUDA source code 3910 depictedin FIG. 40 except for a kernel call that causes kernel MatAdd to executeon a device. In at least one embodiment, kernel MatAdd is defined in HIPsource code 3930 with the same “_global_” declaration specifier withwhich kernel MatAdd is defined in CUDA source code 3910. In at least oneembodiment, a kernel call in HIP source code 3930 is“hipLaunchKernelGGL(MatAdd, numBlocks, threadsPerBlock, 0, 0, A, B,C);”, while a corresponding kernel call in CUDA source code 3910 is“MatAdd<<<numBlocks, threadsPerBlock>>>(A, B, C);”.

FIG. 41 illustrates non-CUDA-enabled GPU 3992 of FIG. 39C in greaterdetail, in accordance with at least one embodiment. In at least oneembodiment, GPU 3992 is developed by AMD corporation of Santa Clara. Inat least one embodiment, GPU 3992 can be configured to perform computeoperations in a highly-parallel fashion. In at least one embodiment, GPU3992 is configured to execute graphics pipeline operations such as drawcommands, pixel operations, geometric computations, and other operationsassociated with rendering an image to a display. In at least oneembodiment, GPU 3992 is configured to execute operations unrelated tographics. In at least one embodiment, GPU 3992 is configured to executeboth operations related to graphics and operations unrelated tographics. In at least one embodiment, GPU 3992 can be configured toexecute device code included in HIP source code 3930.

In at least one embodiment, GPU 3992 includes, without limitation, anynumber of programmable processing units 4120, a command processor 4110,an L2 cache 4122, memory controllers 4170, DMA engines 4180(1), systemmemory controllers 4182, DMA engines 4180(2), and GPU controllers 4184.In at least one embodiment, each programmable processing unit 4120includes, without limitation, a workload manager 4130 and any number ofcompute units 4140. In at least one embodiment, command processor 4110reads commands from one or more command queues (not shown) anddistributes commands to workload managers 4130. In at least oneembodiment, for each programmable processing unit 4120, associatedworkload manager 4130 distributes work to compute units 4140 included inprogrammable processing unit 4120. In at least one embodiment, eachcompute unit 4140 may execute any number of thread blocks, but eachthread block executes on a single compute unit 4140. In at least oneembodiment, a workgroup is a thread block.

In at least one embodiment, each compute unit 4140 includes, withoutlimitation, any number of SIMD units 4150 and a shared memory 4160. Inat least one embodiment, each SIMD unit 4150 implements a SIMDarchitecture and is configured to perform operations in parallel. In atleast one embodiment, each SIMD unit 4150 includes, without limitation,a vector ALU 4152 and a vector register file 4154. In at least oneembodiment, each SIMD unit 4150 executes a different warp. In at leastone embodiment, a warp is a group of threads (e.g., 16 threads), whereeach thread in the warp belongs to a single thread block and isconfigured to process a different set of data based on a single set ofinstructions. In at least one embodiment, predication can be used todisable one or more threads in a warp. In at least one embodiment, alane is a thread. In at least one embodiment, a work item is a thread.In at least one embodiment, a wavefront is a warp. In at least oneembodiment, different wavefronts in a thread block may synchronizetogether and communicate via shared memory 4160.

In at least one embodiment, programmable processing units 4120 arereferred to as “shader engines.” In at least one embodiment, eachprogrammable processing unit 4120 includes, without limitation, anyamount of dedicated graphics hardware in addition to compute units 4140.In at least one embodiment, each programmable processing unit 4120includes, without limitation, any number (including zero) of geometryprocessors, any number (including zero) of rasterizers, any number(including zero) of render back ends, workload manager 4130, and anynumber of compute units 4140.

In at least one embodiment, compute units 4140 share L2 cache 4122. Inat least one embodiment, L2 cache 4122 is partitioned. In at least oneembodiment, a GPU memory 4190 is accessible by all compute units 4140 inGPU 3992. In at least one embodiment, memory controllers 4170 and systemmemory controllers 4182 facilitate data transfers between GPU 3992 and ahost, and DMA engines 4180(1) enable asynchronous memory transfersbetween GPU 3992 and such a host. In at least one embodiment, memorycontrollers 4170 and GPU controllers 4184 facilitate data transfersbetween GPU 3992 and other GPUs 3992, and DMA engines 4180(2) enableasynchronous memory transfers between GPU 3992 and other GPUs 3992.

In at least one embodiment, GPU 3992 includes, without limitation, anyamount and type of system interconnect that facilitates data and controltransmissions across any number and type of directly or indirectlylinked components that may be internal or external to GPU 3992. In atleast one embodiment, GPU 3992 includes, without limitation, any numberand type of I/O interfaces (e.g., PCIe) that are coupled to any numberand type of peripheral devices. In at least one embodiment, GPU 3992 mayinclude, without limitation, any number (including zero) of displayengines and any number (including zero) of multimedia engines. In atleast one embodiment, GPU 3992 implements a memory subsystem thatincludes, without limitation, any amount and type of memory controllers(e.g., memory controllers 4170 and system memory controllers 4182) andmemory devices (e.g., shared memories 4160) that may be dedicated to onecomponent or shared among multiple components. In at least oneembodiment, GPU 3992 implements a cache subsystem that includes, withoutlimitation, one or more cache memories (e.g., L2 cache 4122) that mayeach be private to or shared between any number of components (e.g.,SIMD units 4150, compute units 4140, and programmable processing units4120).

FIG. 42 illustrates how threads of an exemplary CUDA grid 4220 aremapped to different compute units 4140 of FIG. 41 , in accordance withat least one embodiment. In at least one embodiment and for explanatorypurposes only, grid 4220 has a GridSize of BX by BY by 1 and a BlockSizeof TX by TY by 1. In at least one embodiment, grid 4220 thereforeincludes, without limitation, (BX*BY) thread blocks 4230 and each threadblock 4230 includes, without limitation, (TX*TY) threads 4240. Threads4240 are depicted in FIG. 42 as squiggly arrows.

In at least one embodiment, grid 4220 is mapped to programmableprocessing unit 4120(1) that includes, without limitation, compute units4140(1)-4140(C). In at least one embodiment and as shown, (BJ*BY) threadblocks 4230 are mapped to compute unit 4140(1), and the remaining threadblocks 4230 are mapped to compute unit 4140(2). In at least oneembodiment, each thread block 4230 may include, without limitation, anynumber of warps, and each warp is mapped to a different SIMD unit 4150of FIG. 41 .

In at least one embodiment, warps in a given thread block 4230 maysynchronize together and communicate through shared memory 4160 includedin associated compute unit 4140. For example and in at least oneembodiment, warps in thread block 4230(BJ,1) can synchronize togetherand communicate through shared memory 4160(1). For example and in atleast one embodiment, warps in thread block 4230(BJ+1,1) can synchronizetogether and communicate through shared memory 4160(2).

FIG. 43 illustrates how to migrate existing CUDA code to Data ParallelC++ code, in accordance with at least one embodiment. Data Parallel C++(DPC++) may refer to an open, standards-based alternative tosingle-architecture proprietary languages that allows developers toreuse code across hardware targets (CPUs and accelerators such as GPUsand FPGAs) and also perform custom tuning for a specific accelerator.DPC++ use similar and/or identical C and C++ constructs in accordancewith ISO C++ which developers may be familiar with. DPC++ incorporatesstandard SYCL from The Khronos Group to support data parallelism andheterogeneous programming. SYCL refers to a cross-platform abstractionlayer that builds on underlying concepts, portability and efficiency ofOpenCL that enables code for heterogeneous processors to be written in a“single-source” style using standard C++. SYCL may enable single sourcedevelopment where C++ template functions can contain both host anddevice code to construct complex algorithms that use OpenCLacceleration, and then re-use them throughout their source code ondifferent types of data.

In at least one embodiment, a DPC++ compiler is used to compile DPC++source code which can be deployed across diverse hardware targets. In atleast one embodiment, a DPC++ compiler is used to generate DPC++applications that can be deployed across diverse hardware targets and aDPC++ compatibility tool can be used to migrate CUDA applications to amultiplatform program in DPC++. In at least one embodiment, a DPC++ basetool kit includes a DPC++ compiler to deploy applications across diversehardware targets; a DPC++ library to increase productivity andperformance across CPUs, GPUs, and FPGAs; a DPC++ compatibility tool tomigrate CUDA applications to multi-platform applications; and anysuitable combination thereof.

In at least one embodiment, a DPC++ programming model is utilized tosimply one or more aspects relating to programming CPUs and acceleratorsby using modern C++ features to express parallelism with a programminglanguage called Data Parallel C++. DPC++ programming language may beutilized to code reuse for hosts (e.g., a CPU) and accelerators (e.g., aGPU or FPGA) using a single source language, with execution and memorydependencies being clearly communicated. Mappings within DPC++ code canbe used to transition an application to run on a hardware or set ofhardware devices that best accelerates a workload. A host may beavailable to simplify development and debugging of device code, even onplatforms that do not have an accelerator available.

In at least one embodiment, CUDA source code 4300 is provided as aninput to a DPC++ compatibility tool 4302 to generate human readableDPC++ 4304. In at least one embodiment, human readable DPC++ 4304includes inline comments generated by DPC++ compatibility tool 4302 thatguides a developer on how and/or where to modify DPC++ code to completecoding and tuning to desired performance 4306, thereby generating DPC++source code 4308.

In at least one embodiment, CUDA source code 4300 is or includes acollection of human-readable source code in a CUDA programming language.In at least one embodiment, CUDA source code 4300 is human-readablesource code in a CUDA programming language. In at least one embodiment,a CUDA programming language is an extension of the C++ programminglanguage that includes, without limitation, mechanisms to define devicecode and distinguish between device code and host code. In at least oneembodiment, device code is source code that, after compilation, isexecutable on a device (e.g., GPU or FPGA) and may include or moreparallelizable workflows that can be executed on one or more processorcores of a device. In at least one embodiment, a device may be aprocessor that is optimized for parallel instruction processing, such asCUDA-enabled GPU, GPU, or another GPGPU, etc. In at least oneembodiment, host code is source code that, after compilation, isexecutable on a host. In least one embodiment, some or all of host codeand device code can be executed in parallel across a CPU and GPU/FPGA.In at least one embodiment, a host is a processor that is optimized forsequential instruction processing, such as CPU. CUDA source code 4300described in connection with FIG. 43 may be in accordance with thosediscussed elsewhere in this document.

In at least one embodiment, DPC++ compatibility tool 4302 refers to anexecutable tool, program, application, or any other suitable type oftool that is used to facilitate migration of CUDA source code 4300 toDPC++ source code 4308. In at least one embodiment, DPC++ compatibilitytool 4302 is a command-line-based code migration tool available as partof a DPC++ tool kit that is used to port existing CUDA sources to DPC++.In at least one embodiment, DPC++ compatibility tool 4302 converts someor all source code of a CUDA application from CUDA to DPC++ andgenerates a resulting file that is written at least partially in DPC++,referred to as human readable DPC++ 4304. In at least one embodiment,human readable DPC++ 4304 includes comments that are generated by DPC++compatibility tool 4302 to indicate where user intervention may benecessary. In at least one embodiment, user intervention is necessarywhen CUDA source code 4300 calls a CUDA API that has no analogous DPC++API; other examples where user intervention is required are discussedlater in greater detail.

In at least one embodiment, a workflow for migrating CUDA source code4300 (e.g., application or portion thereof) includes creating one ormore compilation database files; migrating CUDA to DPC++ using a DPC++compatibility tool 4302; completing migration and verifying correctness,thereby generating DPC++ source code 4308; and compiling DPC++ sourcecode 4308 with a DPC++ compiler to generate a DPC++ application. In atleast one embodiment, a compatibility tool provides a utility thatintercepts commands used when Makefile executes and stores them in acompilation database file. In at least one embodiment, a file is storedin JSON format. In at least one embodiment, an intercept-built commandconverts Makefile command to a DPC compatibility command.

In at least one embodiment, intercept-build is a utility script thatintercepts a build process to capture compilation options, macro defs,and include paths, and writes this data to a compilation database file.In at least one embodiment, a compilation database file is a JSON file.In at least one embodiment, DPC++ compatibility tool 4302 parses acompilation database and applies options when migrating input sources.In at least one embodiment, use of intercept-build is optional, buthighly recommended for Make or CMake based environments. In at least oneembodiment, a migration database includes commands, directories, andfiles: command may include necessary compilation flags; directory mayinclude paths to header files; file may include paths to CUDA files.

In at least one embodiment, DPC++ compatibility tool 4302 migrates CUDAcode (e.g., applications) written in CUDA to DPC++ by generating DPC++wherever possible. In at least one embodiment, DPC++ compatibility tool4302 is available as part of a tool kit. In at least one embodiment, aDPC++ tool kit includes an intercept-build tool. In at least oneembodiment, an intercept-built tool creates a compilation database thatcaptures compilation commands to migrate CUDA files. In at least oneembodiment, a compilation database generated by an intercept-built toolis used by DPC++ compatibility tool 4302 to migrate CUDA code to DPC++.In at least one embodiment, non-CUDA C++ code and files are migrated asis. In at least one embodiment, DPC++ compatibility tool 4302 generateshuman readable DPC++ 4304 which may be DPC++ code that, as generated byDPC++ compatibility tool 4302, cannot be compiled by DPC++ compiler andrequires additional plumbing for verifying portions of code that werenot migrated correctly, and may involve manual intervention, such as bya developer. In at least one embodiment, DPC++ compatibility tool 4302provides hints or tools embedded in code to help developers manuallymigrate additional code that could not be migrated automatically. In atleast one embodiment, migration is a one-time activity for a sourcefile, project, or application.

In at least one embodiment, DPC++ compatibility tool 43002 is able tosuccessfully migrate all portions of CUDA code to DPC++ and there maysimply be an optional step for manually verifying and tuning performanceof DPC++ source code that was generated. In at least one embodiment,DPC++ compatibility tool 4302 directly generates DPC++ source code 4308which is compiled by a DPC++ compiler without requiring or utilizinghuman intervention to modify DPC++ code generated by DPC++ compatibilitytool 4302. In at least one embodiment, DPC++ compatibility toolgenerates compile-able DPC++ code which can be optionally tuned by adeveloper for performance, readability, maintainability, other variousconsiderations; or any combination thereof.

In at least one embodiment, one or more CUDA source files are migratedto DPC++ source files at least partially using DPC++ compatibility tool4302. In at least one embodiment, CUDA source code includes one or moreheader files which may include CUDA header files. In at least oneembodiment, a CUDA source file includes a <cuda.h> header file and a<stdio.h> header file which can be used to print text. In at least oneembodiment, a portion of a vector addition kernel CUDA source file maybe written as or related to:

  #include <cuda.h> #include <stdio.h> #define VECTOR_SIZE 256 []global__ void VectorAddKernel(float* A, float* B, float* C) { A[threadIdx.x] = threadIdx.x + 1.0f;  B[threadIdx.x] = threadIdx.x +1.0f;  C[threadIdx.x] = A[threadIdx.x] + B[threadIdx.x]; } int main( ) { float *d_A, *d_B, *d_C;  cudaMalloc(&d_A, VECTOR_SIZE*sizeof(float)); cudaMalloc(&d_B, VECTOR_SIZE*sizeof(float));  cudaMalloc(&d_C,VECTOR_SIZE*sizeof(float));  VectorAddKernel<<<1, VECTOR_SIZE>>>(d_A,d_B, d_C);  float Result[VECTOR_SIZE] = { };  cudaMemcpy(Result, d_C,VECTOR_SIZE*sizeof(float), cudaMemcpyDeviceToHost);  cudaFree(d_A); cudaFree(d_B);  cudaFree(d_C);  for (int i=0; i<VECTOR_SIZE; i++ {   if(i % 16 == 0) {    printf(″\n″);   }   printf(″%f″, Result[i]);  } return 0; }

In at least one embodiment and in connection with CUDA source filepresented above, DPC++ compatibility tool 4302 parses a CUDA source codeand replaces header files with appropriate DPC++ and SYCL header files.In at least one embodiment, DPC++ header files includes helperdeclarations. In CUDA, there is a concept of a thread ID andcorrespondingly, in DPC++ or SYCL, for each element there is a localidentifier.

In at least one embodiment and in connection with CUDA source filepresented above, there are two vectors A and B which are initialized anda vector addition result is put into vector C as part ofVectorAddKernel( ). In at least one embodiment, DPC++ compatibility tool4302 converts CUDA thread IDs used to index work elements to SYCLstandard addressing for work elements via a local ID as part ofmigrating CUDA code to DPC++ code. In at least one embodiment, DPC++code generated by DPC++ compatibility tool 4302 can be optimized—forexample, by reducing dimensionality of an nd_item, thereby increasingmemory and/or processor utilization.

In at least one embodiment and in connection with CUDA source filepresented above, memory allocation is migrated. In at least oneembodiment, cudaMalloc( ) is migrated to a unified shared memory SYCLcall malloc_device( ) to which a device and context is passed, relyingon SYCL concepts such as platform, device, context, and queue. In atleast one embodiment, a SYCL platform can have multiple devices (e.g.,host and GPU devices); a device may have multiple queues to which jobscan be submitted; each device may have a context; and a context may havemultiple devices and manage shared memory objects.

In at least one embodiment and in connection with CUDA source filepresented above, a main( ) function invokes or calls VectorAddKernel( )to add two vectors A and B together and store result in vector C. In atleast one embodiment, CUDA code to invoke VectorAddKernel( ) is replacedby DPC++ code to submit a kernel to a command queue for execution. In atleast one embodiment, a command group handler cgh passes data,synchronization, and computation that is submitted to the queue,parallel_for is called for a number of global elements and a number ofwork items in that work group where VectorAddKernel( ) is called.

In at least one embodiment and in connection with CUDA source filepresented above, CUDA calls to copy device memory and then free memoryfor vectors A, B, and C are migrated to corresponding DPC++ calls. In atleast one embodiment, C++ code (e.g., standard ISO C++ code for printinga vector of floating point variables) is migrated as is, without beingmodified by DPC++ compatibility tool 4302. In at least one embodiment,DPC++ compatibility tool 4302 modify CUDA APIs for memory setup and/orhost calls to execute kernel on the acceleration device. In at least oneembodiment and in connection with CUDA source file presented above, acorresponding human readable DPC++ 4304 (e.g., which can be compiled) iswritten as or related to:

  #include <CL/sycl.hpp> #include <dpct/dpct.hpp> #define VECTOR_SIZE256 void VectorAddKernel(float* A, float* B, float* C, sycl::nd_item<3>item_ct1) {  A[item_ct1.get_local_id(2)] = item_ct1.get_local_id(2) +1.0f;  B[item_ct1.get_local_id(2)] = item_ct1.get_local_id(2) + 1.0f; C[item_ct1.get_local_id(2)] =    A[item_ct1.get_local_id(2)] +B[item_ct1.get_local_id(2)]; } int main( ) {  float *d_A, *d_B, *d_C; d_A = (float *)sycl::malloc_device(VECTOR_SIZE * sizeof(float),dpct::get_current_device ( ), dpct::get_default_context( ));  d_B =(float *)sycl::malloc_device(VECTOR_SIZE * sizeof(float),dpct::get_current_device( ), dpct::get_default_context( ));  d_C =(float *)sycl::malloc_device(VECTOR_SIZE * sizeof(float),dpct::get_current_device( ), dpct::get_default_context( )); dpct::get_default_queue_wait( ).submit([&](sycl::handler &cgh) {  cgh.parallel_for(    sycl::nd_range<3>(sycl::range<3>(1, 1, 1) *sycl::range<3>(1, 1, VECTOR_SIZE) * sycl::range<3>(1, 1, VECTOR_SIZE)),   [=](sycl::nd_items<3> item_ct1) {     VectorAddKernel(d_A, d_B, d_C,item_ct1);    });  });  float Result[VECTOR_SIZE] = { }; dpct::get_default_queue_wait( )   .memcpy(Result, d_C, VECTOR_SIZE *sizeof(float))   .wait( );  sycl::free(d_A, dpct::get_default_context());  sycl::free(d_B, dpct::get_default_context( ));  sycl::free(d_C,dpct::get_default_context( ));  for (int i=0; i<VECTOR_SIZE; i++ {   if(i % 16 == 0) {    printf(″\n″);   }   printf(″%f″, Result[i]);  } return 0; }

In at least one embodiment, human readable DPC++ 4304 refers to outputgenerated by DPC++ compatibility tool 4302 and may be optimized in onemanner or another. In at least one embodiment, human readable DPC++ 4304generated by DPC++ compatibility tool 4302 can be manually edited by adeveloper after migration to make it more maintainable, performance, orother considerations. In at least one embodiment, DPC++ code generatedby DPC++ compatibility tool 43002 such as DPC++ disclosed can beoptimized by removing repeat calls to get_current_device( ) and/orget_default_context( ) for each malloc_device( ) call. In at least oneembodiment, DPC++ code generated above uses a 3 dimensional nd_rangewhich can be refactored to use only a single dimension, thereby reducingmemory usage. In at least one embodiment, a developer can manually editDPC++ code generated by DPC++ compatibility tool 4302 replace uses ofunified shared memory with accessors. In at least one embodiment, DPC++compatibility tool 4302 has an option to change how it migrates CUDAcode to DPC++ code. In at least one embodiment, DPC++ compatibility tool4302 is verbose because it is using a general template to migrate CUDAcode to DPC++ code that works for a large number of cases.

In at least one embodiment, a CUDA to DPC++ migration workflow includessteps to: prepare for migration using intercept-build script; performmigration of CUDA projects to DPC++ using DPC++ compatibility tool 4302;review and edit migrated source files manually for completion andcorrectness; and compile final DPC++ code to generate a DPC++application. In at least one embodiment, manual review of DPC++ sourcecode may be required in one or more scenarios including but not limitedto: migrated API does not return error code (CUDA code can return anerror code which can then be consumed by the application but SYCL usesexceptions to report errors, and therefore does not use error codes tosurface errors); CUDA compute capability dependent logic is notsupported by DPC++; statement could not be removed. In at least oneembodiment, scenarios in which DPC++ code requires manual interventionmay include, without limitation: error code logic replaced with (*,0)code or commented out; equivalent DPC++ API not available; CUDA computecapability-dependent logic; hardware-dependent API (clock( )); missingfeatures unsupported API; execution time measurement logic; handlingbuilt-in vector type conflicts; migration of cuBLAS API; and more.

Other variations are within spirit of present disclosure. Thus, whiledisclosed techniques are susceptible to various modifications andalternative constructions, certain illustrated embodiments thereof areshown in drawings and have been described above in detail. It should beunderstood, however, that there is no intention to limit disclosure tospecific form or forms disclosed, but on contrary, intention is to coverall modifications, alternative constructions, and equivalents fallingwithin spirit and scope of disclosure, as defined in appended claims.

Use of terms “a” and “an” and “the” and similar referents in context ofdescribing disclosed embodiments (especially in context of followingclaims) are to be construed to cover both singular and plural, unlessotherwise indicated herein or clearly contradicted by context, and notas a definition of a term. Terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms (meaning“including, but not limited to,”) unless otherwise noted. term“connected,” when unmodified and referring to physical connections, isto be construed as partly or wholly contained within, attached to, orjoined together, even if there is something intervening. Recitation ofranges of values herein are merely intended to serve as a shorthandmethod of referring individually to each separate value falling withinrange, unless otherwise indicated herein and each separate value isincorporated into specification as if it were individually recitedherein. Use of term “set” (e.g., “a set of items”) or “subset” unlessotherwise noted or contradicted by context, is to be construed as anonempty collection comprising one or more members. Further, unlessotherwise noted or contradicted by context, term “subset” of acorresponding set does not necessarily denote a proper subset ofcorresponding set, but subset and corresponding set may be equal.

Conjunctive language, such as phrases of form “at least one of A, B, andC,” or “at least one of A, B and C,” unless specifically statedotherwise or otherwise clearly contradicted by context, is otherwiseunderstood with context as used in general to present that an item,term, etc., may be either A or B or C, or any nonempty subset of set ofA and B and C. For instance, in illustrative example of a set havingthree members, conjunctive phrases “at least one of A, B, and C” and “atleast one of A, B and C” refer to any of following sets: {A}, {B}, {C},{A, B}, {A, C}, {B, C}, {A, B, C}. Thus, such conjunctive language isnot generally intended to imply that certain embodiments require atleast one of A, at least one of B and at least one of C each to bepresent. In addition, unless otherwise noted or contradicted by context,term “plurality” indicates a state of being plural (e.g., “a pluralityof items” indicates multiple items). Number of items in a plurality isat least two, but can be more when so indicated either explicitly or bycontext. Further, unless stated otherwise or otherwise clear fromcontext, phrase “based on” means “based at least in part on” and not“based solely on.”

Operations of processes described herein can be performed in anysuitable order unless otherwise indicated herein or otherwise clearlycontradicted by context. In at least one embodiment, a process such asthose processes described herein (or variations and/or combinationsthereof) is performed under control of one or more computer systemsconfigured with executable instructions and is implemented as code(e.g., executable instructions, one or more computer programs or one ormore applications) executing collectively on one or more processors, byhardware or combinations thereof. In at least one embodiment, code isstored on a computer-readable storage medium, for example, in form of acomputer program comprising a plurality of instructions executable byone or more processors. In at least one embodiment, a computer-readablestorage medium is a non-transitory computer-readable storage medium thatexcludes transitory signals (e.g., a propagating transient electric orelectromagnetic transmission) but includes non-transitory data storagecircuitry (e.g., buffers, cache, and queues) within transceivers oftransitory signals. In at least one embodiment, code (e.g., executablecode or source code) is stored on a set of one or more non-transitorycomputer-readable storage media having stored thereon executableinstructions (or other memory to store executable instructions) that,when executed (i.e., as a result of being executed) by one or moreprocessors of a computer system, cause computer system to performoperations described herein. Set of non-transitory computer-readablestorage media, in at least one embodiment, comprises multiplenon-transitory computer-readable storage media and one or more ofindividual non-transitory storage media of multiple non-transitorycomputer-readable storage media lack all of code while multiplenon-transitory computer-readable storage media collectively store all ofcode. In at least one embodiment, executable instructions are executedsuch that different instructions are executed by differentprocessors—for example, a non-transitory computer-readable storagemedium store instructions and a main central processing unit (“CPU”)executes some of instructions while a graphics processing unit (“GPU”)executes other instructions. In at least one embodiment, differentcomponents of a computer system have separate processors and differentprocessors execute different subsets of instructions.

Accordingly, in at least one embodiment, computer systems are configuredto implement one or more services that singly or collectively performoperations of processes described herein and such computer systems areconfigured with applicable hardware and/or software that enableperformance of operations. Further, a computer system that implements atleast one embodiment of present disclosure is a single device and, inanother embodiment, is a distributed computer system comprising multipledevices that operate differently such that distributed computer systemperforms operations described herein and such that a single device doesnot perform all operations.

At least one embodiment of the disclosure can be described in view ofthe following clauses:

-   -   1. A system, comprising:        -   at least one processor;        -   at least one memory comprising instructions that, in            response to execution by the at least one processor, cause            the system to at least:        -   select a set of lights from among a plurality of lights            associated with a virtual scene, the set of lights selected            based, at least in part, on a first one or more random            factors;        -   select, based at least in part on a second one or more            random factors, a subset of lights from the set of lights,            the subset of lights to be used to generate a frame of            graphics, wherein the subset of lights is selected so that            data indicative of the subset has a total size less than            memory predicted to be available in a processor cache; and        -   render a pixel of the frame of graphics based, at least in            part, on the subset of lights.    -   2. The system of clause 1, the at least one memory comprising        further instructions that, in response to execution by the at        least one processor, cause the system to at least:    -   select an additional set of lights to use to generate an        additional frame of graphics, the additional set of lights        selected from among the plurality of lights associated with the        virtual scene.    -   3. The system of clauses 1 or 2, the at least one memory        comprising further instructions that, in response to execution        by the at least one processor, cause the system to at least:    -   render a second pixel of the frame of graphics using a second        subset of lights selected from the set of lights.    -   4. The system of any of clauses 1-3, wherein the pixel is one of        a plurality of pixels in a first tile of the frame of graphics,        and wherein pixels in a second tile are rendered using a        different subset of lights.    -   5. The system of any of clauses 1-4, the at least one memory        comprising further instructions that, in response to execution        by the at least one processor, cause the system to at least:    -   render a plurality of tiles of the frame of graphics using the        subset of lights, the plurality of tiles non-contiguous in the        frame of graphics, the plurality of tiles rendered consecutively        to preserve residency of the subset of lights in the processor        cache.    -   6. The system of any of clauses 1-5, the at least one memory        comprising further instructions that, in response to execution        by the at least one processor, cause the system to at least:    -   shuffle one or more lights from the subset of lights into an        additional subset of lights; and    -   use the additional subset of lights to render an additional        pixel of the frame of graphics.    -   7. The system of any of clauses 1-6, wherein the subset of        lights is selected to have a total size that is less than an        amount of processor cache memory available during rendering of        the frame of graphics.    -   8. The system of any of clauses 1-7, wherein the first one or        more random factors are weighted to favor selection of lights        based, at least in part, on intensity of a selected light.    -   9. A method, comprising:    -   selecting, based at least in part on a first one or more random        factors, a set of lights from a plurality of lights associated        with a virtual scene;    -   generating a frame of graphics using lights from the set of        lights, by at least:        -   selecting, based at least in part on a second one or more            random factors, a subset of lights from the set of lights;            and        -   rendering a pixel of the frame of graphics based, at least            in part, on the subset of lights.    -   10. The method of clause 9, further comprising:    -   generating an additional frame of graphics using an additional        set of lights, the additional set of lights selected from among        the plurality of lights associated with the virtual scene.    -   11. The method of clauses 9 or 10, further comprising:    -   rendering a second pixel of the frame of graphics using a second        subset of lights selected from the set of lights.    -   12. The method of any of clauses 9-11, further comprising:    -   rendering pixels in different tiles of the frame of graphics        using a different subset of lights.    -   13. The method of any of clauses 9-12, further comprising:    -   rendering a plurality of tiles of the frame of graphics using        the subset of lights, the plurality of tiles non-contiguous in        the frame of graphics and rendered consecutively.    -   14. The method of any of clauses 9-13, further comprising:    -   selecting the subset of lights to have a size less than a        processor cache size.    -   15. The method of any of clauses 9-14, further comprising:    -   generating an additional subset of lights based, at least in        part, on randomly selecting at least a portion of the subset of        lights for inclusion in the additional subset of lights; and    -   generating an additional tile of the frame of graphics using the        additional subset of lights.    -   16. The method of any of clauses 9-15, further comprising:    -   generating an additional subset of lights by at least replacing        a portion of the subset of lights with one or more additional        lights selected from the set of lights.    -   17. A non-transitory computer-readable storage medium comprising        instructions that, in response to execution by at least one        processor of a computing device, cause the computing device to        at least:    -   select a set of lights from among lights associated with a        virtual scene, the set of lights selected at least partially at        random, wherein a frame of graphics is to be rendered based, at        least in part, on the set of lights; and    -   generate a portion of the frame of graphics using a subset of        lights from the set of lights, the subset of lights selected at        least partially at random from the set of lights, wherein a        pixel of the portion of the frame of graphics is rendered based        at least in part on the subset of lights.    -   18. The non-transitory computer-readable storage medium of        clause 17, comprising further instructions that, in response to        execution by at least one processor of the computing device,        cause the computing device to at least:    -   generate an additional frame of graphics using an additional set        of lights, the additional set of lights selected from among the        lights associated with the virtual scene.    -   19. The non-transitory computer-readable storage medium of        clauses 17 or 18, comprising further instructions that, in        response to execution by at least one processor of the computing        device, cause the computing device to at least:    -   render pixels in different portions of the frame of graphics        using a different subset of lights.    -   20. The non-transitory computer-readable storage medium of any        of clauses 17-19, comprising further instructions that, in        response to execution by at least one processor of the computing        device, cause the computing device to at least:    -   render a plurality of portions of the frame of graphics using        the subset of lights, the plurality of portions rendered        consecutively.    -   21. The non-transitory computer-readable storage medium of any        of clauses 17-20, comprising further instructions that, in        response to execution by at least one processor of the computing        device, cause the computing device to at least:    -   generate an additional subset of lights based, at least in part,        on selecting one or more lights from the subset of lights.    -   22. The non-transitory computer-readable storage medium of any        of clauses 17-21, wherein a majority of lights in the subset of        lights remain resident in a processor cache during rendering of        one or more portions of the frame of graphics.    -   23. The non-transitory computer-readable storage medium of any        of clauses 17-22, wherein the set of lights and subset of lights        are selected based, at least in part, on at least one of        intensity of a selected light or distance to the selected light.

Use of any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate embodiments ofdisclosure and does not pose a limitation on scope of disclosure unlessotherwise claimed. No language in specification should be construed asindicating any non-claimed element as essential to practice ofdisclosure.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

In description and claims, terms “coupled” and “connected,” along withtheir derivatives, may be used. It should be understood that these termsmay be not intended as synonyms for each other. Rather, in particularexamples, “connected” or “coupled” may be used to indicate that two ormore elements are in direct or indirect physical or electrical contactwith each other. “Coupled” may also mean that two or more elements arenot in direct contact with each other, but yet still co-operate orinteract with each other.

Unless specifically stated otherwise, it may be appreciated thatthroughout specification terms such as “processing,” “computing,”“calculating,” “determining,” or like, refer to action and/or processesof a computer or computing system, or similar electronic computingdevice, that manipulate and/or transform data represented as physical,such as electronic, quantities within computing system's registersand/or memories into other data similarly represented as physicalquantities within computing system's memories, registers or other suchinformation storage, transmission or display devices.

In a similar manner, term “processor” may refer to any device or portionof a device that processes electronic data from registers and/or memoryand transform that electronic data into other electronic data that maybe stored in registers and/or memory. As non-limiting examples,“processor” may be a CPU or a GPU. A “computing platform” may compriseone or more processors. As used herein, “software” processes mayinclude, for example, software and/or hardware entities that performwork over time, such as tasks, threads, and intelligent agents. Also,each process may refer to multiple processes, for carrying outinstructions in sequence or in parallel, continuously or intermittently.Terms “system” and “method” are used herein interchangeably insofar assystem may embody one or more methods and methods may be considered asystem.

In present document, references may be made to obtaining, acquiring,receiving, or inputting analog or digital data into a subsystem,computer system, or computer-implemented machine. Process of obtaining,acquiring, receiving, or inputting analog and digital data can beaccomplished in a variety of ways such as by receiving data as aparameter of a function call or a call to an application programminginterface. In some implementations, process of obtaining, acquiring,receiving, or inputting analog or digital data can be accomplished bytransferring data via a serial or parallel interface. In anotherimplementation, process of obtaining, acquiring, receiving, or inputtinganalog or digital data can be accomplished by transferring data via acomputer network from providing entity to acquiring entity. Referencesmay also be made to providing, outputting, transmitting, sending, orpresenting analog or digital data. In various examples, process ofproviding, outputting, transmitting, sending, or presenting analog ordigital data can be accomplished by transferring data as an input oroutput parameter of a function call, a parameter of an applicationprogramming interface or interprocess communication mechanism.

Although discussion above sets forth example implementations ofdescribed techniques, other architectures may be used to implementdescribed functionality, and are intended to be within scope of thisdisclosure. Furthermore, although specific distributions ofresponsibilities are defined above for purposes of discussion, variousfunctions and responsibilities might be distributed and divided indifferent ways, depending on circumstances.

Furthermore, although subject matter has been described in languagespecific to structural features and/or methodological acts, it is to beunderstood that subject matter claimed in appended claims is notnecessarily limited to specific features or acts described. Rather,specific features and acts are disclosed as exemplary forms ofimplementing the claims.

What is claimed is:
 1. A system, comprising: at least one processor; andat least one memory comprising instructions that, in response toexecution by the at least one processor, cause the system to at least:select a set of light sources from among a plurality of light sourcesassociated with a virtual scene, the set of light sources selectedbased, at least in part, on a first one or more random factors; select,based at least in part on a second one or more random factors, a subsetof light sources from the set of light sources, the subset of lightsources to be used to generate a frame of graphics, wherein the subsetof light sources is selected so that data indicative of the subset has atotal size less than memory predicted to be available in a processorcache; and render a pixel of the frame of graphics based, at least inpart, on the subset of light sources.
 2. The system of claim 1, the atleast one memory comprising further instructions that, in response toexecution by the at least one processor, cause the system to at least:select an additional set of light sources to use to generate anadditional frame of graphics, the additional set of light sourcesselected from among the plurality of light sources associated with thevirtual scene.
 3. The system of claim 1, the at least one memorycomprising further instructions that, in response to execution by the atleast one processor, cause the system to at least: render a second pixelof the frame of graphics using a second subset of light sources selectedfrom the set of light sources.
 4. The system of claim 1, wherein thepixel is one of a plurality of pixels in a first tile of the frame ofgraphics, and wherein pixels in a second tile are rendered using adifferent subset of light sources.
 5. The system of claim 1, the atleast one memory comprising further instructions that, in response toexecution by the at least one processor, cause the system to at least:render a plurality of tiles of the frame of graphics using the subset oflight sources, the plurality of tiles non-contiguous in the frame ofgraphics, the plurality of tiles rendered consecutively to preserveresidency of the subset of light sources in the processor cache.
 6. Thesystem of claim 1, the at least one memory comprising furtherinstructions that, in response to execution by the at least oneprocessor, cause the system to at least: shuffle one or more lightsources from the subset of light sources into an additional subset oflight sources; and use the additional subset of light sources to renderan additional pixel of the frame of graphics.
 7. The system of claim 1,wherein the subset of light sources is selected to have a total sizethat is less than an amount of processor cache memory available duringrendering of the frame of graphics.
 8. The system of claim 1, whereinthe first one or more random factors are weighted to favor selection oflight sources based, at least in part, on intensity of a selected light.9. A method, comprising: selecting, based at least in part on a firstone or more random factors, a set of light sources from a plurality oflight sources associated with a virtual scene; and generating a frame ofgraphics using light sources from the set of light sources, by at least:selecting, based at least in part on a second one or more randomfactors, a subset of light sources from the set of light sources; andrendering a pixel of the frame of graphics based, at least in part, onthe subset of light sources.
 10. The method of claim 9, furthercomprising: generating an additional frame of graphics using anadditional set of light sources, the additional set of light sourcesselected from among the plurality of light sources associated with thevirtual scene.
 11. The method of claim 9, further comprising: renderinga second pixel of the frame of graphics using a second subset of lightsources selected from the set of light sources.
 12. The method of claim9, further comprising: rendering pixels in different tiles of the frameof graphics using a different subset of light sources.
 13. The method ofclaim 9, further comprising: rendering a plurality of tiles of the frameof graphics using the subset of light sources, the plurality of tilesnon-contiguous in the frame of graphics and rendered consecutively. 14.The method of claim 9, further comprising: selecting the subset of lightsources to have a size less than a processor cache size.
 15. The methodof claim 9, further comprising: generating an additional subset of lightsources based, at least in part, on randomly selecting at least aportion of the subset of light sources for inclusion in the additionalsubset of light sources; and generating an additional tile of the frameof graphics using the additional subset of light sources.
 16. The methodof claim 9, further comprising: generating an additional subset of lightsources by at least replacing a portion of the subset of light sourceswith one or more additional light sources selected from the set of lightsources.
 17. A non-transitory computer-readable storage mediumcomprising instructions that, in response to execution by at least oneprocessor of a computing device, cause the computing device to at least:select a set of light sources from among light sources associated with avirtual scene, the set of light sources selected at least partially atrandom, wherein a frame of graphics is to be rendered based, at least inpart, on the set of light sources; and generate a portion of the frameof graphics using a subset of light sources from the set of lightsources, the subset of light sources selected at least partially atrandom from the set of light sources, wherein a pixel of the portion ofthe frame of graphics is rendered based at least in part on the subsetof light sources.
 18. The non-transitory computer-readable storagemedium of claim 17, comprising further instructions that, in response toexecution by at least one processor of the computing device, cause thecomputing device to at least: generate an additional frame of graphicsusing an additional set of light sources, the additional set of lightsources selected from among the light sources associated with thevirtual scene.
 19. The non-transitory computer-readable storage mediumof claim 17, comprising further instructions that, in response toexecution by at least one processor of the computing device, cause thecomputing device to at least: render pixels in different portions of theframe of graphics using a different subset of light sources.
 20. Thenon-transitory computer-readable storage medium of claim 17, comprisingfurther instructions that, in response to execution by at least oneprocessor of the computing device, cause the computing device to atleast: render a plurality of portions of the frame of graphics using thesubset of light sources, the plurality of portions renderedconsecutively.
 21. The non-transitory computer-readable storage mediumof claim 17, comprising further instructions that, in response toexecution by at least one processor of the computing device, cause thecomputing device to at least: generate an additional subset of lightsources based, at least in part, on selecting one or more light sourcesfrom the subset of light sources.
 22. The non-transitorycomputer-readable storage medium of claim 17, wherein a majority oflights in the subset of light sources remain resident in a processorcache during rendering of one or more portions of the frame of graphics.23. The non-transitory computer-readable storage medium of claim 17,wherein the set of light sources and subset of light sources areselected based, at least in part, on at least one of intensity of aselected light source or distance to the selected light source.